WO2016207993A1

WO2016207993A1 - Air conditioner

Info

Publication number: WO2016207993A1
Application number: PCT/JP2015/068141
Authority: WO
Inventors: 博文 ▲高▼下; 博幸岡野; 一輝大河内
Original assignee: 三菱電機株式会社
Priority date: 2015-06-24
Filing date: 2015-06-24
Publication date: 2016-12-29
Also published as: JP6391832B2; GB2557058A; JPWO2016207993A1; GB2557058C; GB201800859D0; GB2557058B

Abstract

In the present invention, an air conditioner has a heat source device, a plurality of indoor devices, and a relay device connected between the heat source device and the plurality of indoor devices via refrigerant pipelines. A heat-source-side heat exchanger includes an upper-stage heat exchanger and a lower-stage heat exchanger that are connected in parallel to a compressor and disposed so as to be aligned in the vertical direction. The heat source device is provided with: a capacity control valve for controlling the flow of refrigerant into the upper-stage heat exchanger and lower-stage heat exchanger to control the capacity of the heat-source-side heat exchanger; a heat-source-side gas-liquid separator for separating the refrigerant flowing in from the relay device into a gas refrigerant and a liquid refrigerant; a first branch pipeline through which the refrigerant that has flowed into the heat-source-side gas-liquid separator is caused to flow through the capacity control valve; a second branch pipeline through which the refrigerant that has flowed into the heat-source-side gas-liquid separator is caused to flow into the lower-stage heat exchanger; and a flow-rate control device provided to the second pipeline, the flow-rate control device adjusting the rate at which refrigerant flows into the lower-stage heat exchanger via the second pipeline.

Description

Air conditioner

The present invention relates to an air conditioner in which a heat source side heat exchanger has a plurality of heat exchange units.

In an air conditioner using a conventional refrigeration cycle (heat pump cycle), a compressor, a heat source unit having a heat source side heat exchanger, a flow control device, and a load side unit (indoor unit) having an indoor unit side heat exchanger Are connected by a refrigerant pipe to constitute a refrigerant circuit for circulating the refrigerant. Then, in the indoor unit side heat exchanger, when the refrigerant evaporates and condenses, the pressure, temperature, etc. relating to the refrigerant in the refrigerant circuit are utilized by utilizing heat absorption and heat radiation from the air in the air-conditioning target space to be heat exchanged. Air conditioning while changing. As the refrigerant used in such an air conditioner, for example, an HFC (hydrofluorocarbon) refrigerant is often used. In addition, one using a natural refrigerant such as carbon dioxide (CO ₂ ) has been proposed.

Further, conventionally, a fin tube type heat exchanger provided with heat transfer tubes and fins is used for the heat source side heat exchanger. As this heat transfer tube, in addition to the circular heat transfer tube shown in Patent Document 1, a flat tube having a cross-sectional shape shown in Patent Document 2 in which a rectangle with a large aspect ratio is cut off is known. Moreover, in patent document 2, the outdoor heat exchanger is divided | segmented up and down into three heat exchange parts, the liquid side connection member and the gas side header are connected to each heat exchange part, and a liquid side connection member or The structure by which a refrigerant | coolant is divided into each heat exchange part from the gas side header is disclosed.

Japanese Patent Laid-Open No. 2-033595 JP 2012-163313 A

As in Patent Document 2, when the heat source side heat exchanger has a plurality of heat exchange sections, the wind speed distribution in each heat exchange section may be different, and it is necessary to distribute the refrigerant in accordance with the wind speed distribution. In particular, when the heat transfer tube as in Patent Document 2 is a flat tube, the performance of the entire heat exchanger may be deteriorated unless the refrigerant flow rate to the upper heat exchanger is increased. On the other hand, as a heat exchanger structure, there is a problem that the structure of the heat exchanger becomes complicated when appropriate refrigerant distribution to each heat exchange unit is attempted.

Therefore, the present invention was made in response to the above problem, and when the heat source side heat exchanger is divided into a plurality of heat exchange parts, without adopting a special structure for the heat source side heat exchanger, It aims at providing the air conditioning apparatus which can perform optimal refrigerant | coolant distribution to several heat exchange parts.

An air conditioner according to the present invention includes a compressor that compresses and discharges a refrigerant, a heat source device including a heat source side heat exchanger that exchanges heat between the refrigerant discharged from the compressor and a heat source medium, the refrigerant, and a utilization medium A plurality of indoor units having a use-side heat exchanger that exchanges heat with each other, a heat-source-side flow controller connected to the use-side heat exchanger, and a refrigerant between the heat source unit and the plurality of indoor units And a relay that is connected via a pipe and distributes the refrigerant flowing out from the heat source side heat exchanger to the plurality of indoor units. The heat source side heat exchanger is connected to the compressor in parallel with each other and arranged in the vertical direction. The heat source unit includes an upper stage heat exchange unit and a lower stage side heat exchange unit, and the capacity of the heat source side heat exchanger is controlled by controlling the flow of refrigerant into the upper stage side heat exchange unit and the lower stage side heat exchange unit. Capacity control valve for controlling the flow rate, and a heat source for separating the refrigerant flowing from the relay into gas refrigerant and liquid refrigerant A gas-liquid separator; a first branch pipe that allows the refrigerant that has flowed into the heat source side gas-liquid separator to flow into the capacity control valve; and a second that causes the refrigerant that has flowed into the heat source side gas-liquid separator to flow into the lower heat exchange section. A branch pipe and a flow rate control device that is provided in the second branch pipe and adjusts the flow rate of the refrigerant flowing into the lower stage heat exchange section via the second branch pipe.

According to the air conditioner of the present invention, by providing a flow rate control device that adjusts the amount of refrigerant in the heat source side heat exchanger, the heat source side heat exchanger itself has a simple structure without providing a special refrigerant distribution. Optimal refrigerant distribution to each heat exchange unit can be performed.

It is a refrigerant circuit figure which shows an example of the air conditioning apparatus which concerns on embodiment of this invention. FIG. 2 is a refrigerant circuit diagram illustrating a refrigerant flow when simultaneous cooling and heating operation mainly performed by the cooling is performed in the air conditioning apparatus of FIG. 1. FIG. 2 is a refrigerant circuit diagram illustrating a refrigerant flow when a heating / cooling simultaneous heating / cooling simultaneous operation is performed in the air conditioning apparatus of FIG. 1. It is a graph which shows the relationship between the flow regulator and heating performance at the time of a heating only operation in the air conditioning apparatus of FIG. It is a flowchart which shows the operation example of the flow control apparatus at the time of the heating and cooling simultaneous operation of the air conditioning apparatus of FIG.2 and FIG.3. It is a flowchart which shows the operation example of the on-off valve when the air conditioning apparatus of FIG. 1 is performing the cooling operation.

Hereinafter, embodiments of the air conditioner of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram illustrating an example of an air-conditioning apparatus according to an embodiment of the present invention. The air conditioner 1 of FIG. 1 performs air conditioning operation using the refrigerating cycle (heat pump cycle) by a refrigerant circulation. In particular, the air conditioner 1 of the present embodiment can perform simultaneous cooling and heating operations in which a plurality of indoor units are mixed with cooling and heating at the same time.

The air conditioner 1 includes a heat source unit 10, a relay unit 20, and a plurality of

indoor units

30A and 30B, and these devices are connected by refrigerant piping. That is, the relay machine 20 for controlling the flow of the refrigerant is provided between the heat source unit 10 and the

indoor units

30A and 30B, and the plurality of

indoor units

30A and 30B are arranged in parallel with each other. 20.

The heat source device 10 and the relay device 20 are connected by a first main pipe 2 and a second main pipe 3 having a smaller diameter than the first main pipe 2. In the first main pipe 2, a high-pressure refrigerant flows from the heat source device 10 side to the relay device 20 side. A refrigerant having a lower pressure flows in the second main pipe 3 than the refrigerant flowing in the first main pipe 2 from the relay machine 20 side to the heat source machine 10 side. Here, the level of the pressure is not determined by the relationship with the reference pressure (numerical value), but by the pressurization of the compressor 11, the control of the open / close state (opening) of each flow control device, or the like. In the refrigerant circuit, it is expressed on the basis of relative height (including the middle). In addition, since the pressure of the refrigerant | coolant discharged from the compressor 11 is the highest and a pressure falls by a flow control apparatus etc., the pressure of the refrigerant | coolant suck | inhaled by the compressor 11 becomes the lowest.

The relay machine 20 and the indoor units 30 </ b> A and 30 </ b> B are connected by the first branch pipe 4 and the second branch pipe 5. A refrigerant circuit in which the refrigerant circulates between the heat source unit 10, the relay unit 20, and the

indoor units

30A, 30B is configured by the pipe connection by the first main pipe 2, the second main pipe 3, the first branch pipe 4, and the second branch pipe 5. Is done.

[Heat source machine 10]
The heat source device 10 includes a compressor 11, a flow path switch 12, a heat source side heat exchanger 13, an accumulator 14, and a flow path forming unit 15. The compressor 11 applies pressure to the sucked refrigerant and discharges it. The compressor 11 includes, for example, a discharge capacity that is a refrigerant discharge amount as a whole, and an inverter compressor that can change the capacity according to the discharge capacity. And the compressor 11 can change a drive frequency arbitrarily based on the instruction | indication of the control apparatus 60 by an inverter circuit (not shown).

The flow path switch 12 is connected to the discharge side of the compressor 11 and switches the flow path corresponding to the form (mode) of cooling and heating based on an instruction from the control device 60, and includes, for example, a four-way valve. ing. The flow path switch 12 includes four ports, and each port includes a discharge side of the compressor 11, a heat source side heat exchanger 13, an accumulator 14, an outlet side of the check valve 15b, and a check valve 15c. Each is connected to the entrance side. The flow path switching unit 12 is used in the cooling only operation in which all the

indoor units

30A and 30B are in the cooling operation and in the cooling main operation in which the cooling is mainly performed in the simultaneous cooling and heating operation, and in the all the

indoor units

30A and 30B. The refrigerant flow path is switched according to the heating-main operation in which heating is mainly performed during all heating operation and heating / cooling simultaneous operation.

The heat source side heat exchanger 13 includes a heat transfer tube through which the refrigerant passes and fins (not shown) for increasing the heat transfer area between the refrigerant flowing through the heat transfer tube and the outside air. ). For example, it functions as an evaporator at the time of all heating operation and heating main operation, and evaporates and evaporates the refrigerant. On the other hand, during the cooling only operation and the cooling main operation, it functions as a condenser and condenses and liquefies the refrigerant. The heat source side heat exchanger 13 exchanges heat between the refrigerant flowing in the heat source side heat exchanger 13 and the refrigerant flowing in the heat source side heat exchanger 13. The refrigerant flowing in the heat source side heat exchanger 13 may be water or brine. Further, the heat source unit 10 may be provided with a heat source unit side blower (not shown) for blowing air to the heat source side heat exchanger 13 and efficiently exchanging heat between the refrigerant and the air.

Here, the heat source side heat exchanger 13 described above is arranged side by side in the vertical direction, and has an upper stage side heat exchange part 13a and a lower stage side heat exchange part 13b connected in parallel to each other. One of the upper stage side heat exchange unit 13 a and the lower stage side heat exchange unit 13 b is connected to the flow path switch 12, and the other is connected to the first main pipe 2. In addition, although illustrated about the case where the heat-source side heat exchanger 13 has the upper stage side heat exchange part 13a divided | segmented into two and the lower stage side heat exchange part 13b, you may divide | segment into two or more.

In particular, the heat source side heat exchanger 13 has a shape in which a cross-sectional shape is a rectangle with a large aspect ratio, and the upper stage side heat exchange unit 13a and the lower stage are divided by dividing one heat exchanger into upper and lower regions. The side heat exchange part 13b is formed. Further, the heat source side heat exchanger 13 is a single-row flat tube heat exchanger having a flat tube through which refrigerant flows and a plurality of plate-like fins into which the flat tube is inserted and joined in a direction perpendicular to the flat tube. Is formed by bonding in two or less rows in the thickness direction. Thereby, since brazing etc. can be performed from the both sides of a heat exchanger, workability is improved. In addition, it is not restricted to the case where it couple | bonds with 2 or less rows, The heat exchanger couple | bonded with 2 or more rows may be sufficient.

The accumulator 14 is connected to the suction side of the compressor 11, separates the liquid refrigerant, and supplies the gas refrigerant to the compressor 11. Regardless of the switching of the flow path by the flow path switch 12, the flow path forming section 15 causes the refrigerant to flow out of the circulation path from the first main pipe 2 and into the second main pipe 3, and each check valve 15a˜ 15c. The check valve 15 a is located on the pipe between the heat source side heat exchanger 13 and the first main pipe 2, and allows refrigerant to flow from the heat source side heat exchanger 13 to the first main pipe 2. The check valve 15 b is located on the pipe between the flow path switch 12 and the second main pipe 3 and allows refrigerant to flow from the second main pipe 3 toward the flow path switch 12. The check valve 15 c is located on the pipe between the flow path switch 12 and the first main pipe 2 and allows the refrigerant to flow in the direction from the flow path switch 12 to the second main pipe 3.

Furthermore, the heat source device 10 includes a capacity control valve 41, a heat source side gas-liquid separator 42, a first branch pipe 43a, a second branch pipe 43b, a third branch pipe 43c, and a flow rate control device 44. The capacity control valve 41 controls the capacity of the heat source side heat exchanger 13 by controlling the inflow of refrigerant into the upper stage side heat exchange section 13a and the lower stage side heat exchange section 13b. The capacity control valve 41 includes an upper stage control valve 41a connected to the upper stage side heat exchanging part 13a, and a lower stage side control valve 41b connected to the lower stage side heat exchanging part 13b. The side heat exchange part 13b consists of a solenoid valve, for example. A check valve 41 x is provided between the capacity control valve 41 and the flow path switch 12. The check valve 41x allows the refrigerant to flow from the flow switching device 12 in the heating flow path, and prevents the refrigerant from flowing from the heat source side gas-liquid separator 42 in the cooling flow path. When the heat source side heat exchanger 13 is divided into three or more, the capacity control valve 41 is provided with a corresponding number of electromagnetic valves.

The heat source side gas-liquid separator 42 separates the refrigerant flowing from the relay machine 20 into a gas refrigerant and a liquid refrigerant. That is, the refrigerant flowing through the plurality of

indoor units

30A and 30B flows into the heat source side gas-liquid separator 42 via the relay unit. A first branch pipe 43a, a second branch pipe 43b, and a third branch pipe 43c are connected to the heat source side gas-liquid separator 42, respectively. The first branch pipe 43 a allows the liquid refrigerant separated in the heat source side gas-liquid separator 42 to flow into the capacity control valve 41. The check valve 16 is provided in the first branch pipe 43a, and the check valve 16 allows the refrigerant to flow from the heat source side gas-liquid separator 42 to the capacity control valve 41 in the first branch pipe 43a. To do.

The second branch pipe 43b allows the liquid refrigerant separated in the second heat source side gas-liquid separator to flow into the lower heat exchange section 13b. The second branch pipe 43b is provided with a flow rate control device 44 composed of, for example, an electronic expansion valve, and the amount of refrigerant flowing into the lower heat exchange section 13b is adjusted by adjusting the opening degree of the flow rate control device 44. Adjusted.

The third branch pipe 43c is connected between the flow path switch 12 and the accumulator 14, and allows the gas refrigerant separated in the heat source side gas-liquid separator 42 to flow into the suction side of the compressor 11. . The third branch pipe 43 c is provided with an on-off valve 45 that controls the inflow of refrigerant from the heat source side gas-liquid separator 42 to the suction side of the compressor 11.

When the cooling channel is formed so that the heat source side heat exchanger 13 becomes a condenser, when the on-off valve 45 is opened, the gas refrigerant separated by the heat source side gas-liquid separator 42 is the third branch pipe 43c. Flows into the accumulator 14. When the on-off valve 45 is closed, the refrigerant flowing from the relay machine 20 does not flow to the first branch pipe 43a but flows to the first branch pipe 43a and the second branch pipe 43b. On the other hand, when the heating flow path is formed so that the heat source side heat exchanger 13 becomes an evaporator, when the on-off valve 45 is opened, the refrigerant flowing from the flow path switching device 12 to the accumulator 14 flows into the third branch pipe. It flows into the heat source side gas-liquid separator 42 through 43c.

Further, the heat source device 10 is provided with a connection pipe 46 that connects between the flow path switch 12 and the check valve 15a (second main pipe 3), and the connection pipe 46 is provided with a check valve 47. ing. And when the cooling channel is formed, the refrigerant that has flowed out of the heat source side heat exchanger 13 flows into the accumulator 14 via the connection pipe 46 and the check valve 47, and when the heating channel is formed, The check valve 47 prevents the refrigerant from flowing into the connection pipe 46.

[Repeater 20]
The repeater 20 includes a repeater-side gas-liquid separator 21, a first inter-refrigerant heat exchanger 22, a first repeater-side flow rate adjuster 23, a second inter-refrigerant heat exchanger 24, and a second repeater-side flow rate adjuster. 25, a first distribution unit 26, and a second distribution unit 27. The repeater side gas-liquid separator 21 separates the refrigerant flowing from the second main pipe 3 into a gas refrigerant and a liquid refrigerant. The repeater side gas-liquid separator 21 is connected to a gas phase pipe 21a from which a gas refrigerant flows out and a liquid phase pipe 21b from which the liquid refrigerant flows out. The gas phase piping 21 a is connected to the first distribution unit 26, and the liquid phase piping 21 b is connected to the first inter-refrigerant heat exchanger 22.

The first inter-refrigerant heat exchanger 22 supercools the liquid refrigerant during the cooling only operation and supplies it to the

indoor units

30A and 30B. The first inter-refrigerant heat exchanger 22 includes a refrigerant that flows from the relay-side gas-liquid separator 21 to the first relay-side flow rate regulator 23, and a refrigerant that flows from the second inter-refrigerant heat exchanger 24 to the second main pipe 3. Heat exchange between.

The first relay-side flow rate regulator 23 is composed of, for example, an electronic expansion valve and is provided between the first inter-refrigerant heat exchanger 22 and the second inter-refrigerant heat exchanger 24. The first relay-side flow rate regulator 23 adjusts the flow rate of refrigerant and the pressure of the refrigerant flowing from the first inter-refrigerant heat exchanger 22 to the second inter-refrigerant heat exchanger 24, and the opening degree is controlled by the control device 60. It is controlled.

The second inter-refrigerant heat exchanger 24 includes a refrigerant that flows from the first relay-side flow rate regulator 23 to the second distributor 27 and a second relay-side flow rate regulator 25 that flows through the first relay-side bypass pipe 28. Heat exchange is performed with the refrigerant in the downstream portion (the refrigerant that has passed through the second relay-side flow rate regulator 25). Here, the 1st relay machine side bypass piping 28 connects between the 2nd refrigerant | coolant heat exchanger 24 and the 2nd distribution part 27, the 2nd refrigerant | coolant heat exchanger 24 and a 2nd distribution part. A part of the refrigerant flowing between the refrigerant and the refrigerant flows into the second inter-refrigerant heat exchanger 24 via the first relay-side bypass pipe 28. Further, the refrigerant that has flowed out of the first relay-side bypass pipe 28 via the second inter-refrigerant heat exchanger 24 flows into the first inter-refrigerant heat exchanger 22. Thus, the 1st refrigerant | coolant heat exchanger 22 and the 2nd refrigerant | coolant heat exchanger 24 supercool a liquid refrigerant at the time of air_conditionaing | cooling operation, and supply it to

indoor unit

30A, 30B side.

The second repeater side flow rate regulator 25 is composed of, for example, an electronic expansion valve and adjusts the refrigerant flow rate and the refrigerant pressure of the refrigerant passing through the first repeater side bypass pipe 28. The opening degree of the second relay-side flow rate regulator 25 is controlled by the control device 60.

In the case of the cooling only operation or the cooling main operation, the refrigerant flowing out from the relay-side gas-liquid separator 21 is the first inter-refrigerant heat exchanger 22, the first relay-side flow rate regulator 23, and the second inter-refrigerant heat exchanger. 24 flows into the second distribution part 27 via 24. On the other hand, the refrigerant that has passed through the second relay-side flow rate regulator 25 and the first relay-side bypass pipe 28 supercools the refrigerant in the second inter-refrigerant heat exchanger 24 and the first inter-refrigerant heat exchanger 22, It flows to the second main pipe 3.

The first distribution unit 26 and the second distribution unit 27 distribute the refrigerant supplied from the heat source unit 10 to the plurality of

indoor units

30A and 30B. The first distribution unit 26 includes a heating on / off valve 26a and a cooling on / off valve 26b connected to the indoor unit 30A and the indoor unit 30B, respectively. The heating on-off valve 26 a is connected to the gas phase pipe 21 a, and the cooling on-off valve 26 b is connected to the second main pipe 3. When the

indoor units

30A and 30B perform the cooling operation, the cooling on-off valve 26b is opened, and the refrigerant flows from the

indoor units

30A and 30B to the heat source unit 10 through the second main pipe 3. At this time, the heating on-off valve 26a is closed. On the other hand, when the

indoor units

30A and 30B perform the heating operation, the heating on-off valve 26a is opened, and the refrigerant flows from the vapor phase pipe 21a to the

indoor units

30A and 30B. At this time, the cooling on-off valve 26b is closed.

In addition, although the 1st distribution part 26 illustrated about the case where it has the heating on-off valve 26a and the cooling on-off valve 26b, for example, each of the

indoor units

30A and 30B is provided with a three-way switching valve, and the second main pipe 3 or You may make it switch a connection with the gaseous-phase piping 21a.

The second distribution unit 27 has a heating check valve 27a and a cooling check valve 27b connected to the indoor unit 30A and the indoor unit 30B, respectively. When the

indoor units

30A and 30B perform the cooling operation, the refrigerant supercooled in the second inter-refrigerant heat exchanger 24 flows to the

indoor units

30A and 30B via the cooling check valve 27b. On the other hand, when the

indoor units

30A and 30B perform the heating operation, the refrigerant that has flowed out of the

indoor units

30A and 30B flows to the second repeater-side bypass pipe 29 via the heating check valve 27a. Here, the second relay-side bypass pipe 29 connects the heating check valve 27 a, the first relay-side flow rate regulator 23, and the second inter-refrigerant heat exchanger 24. In addition, although illustrated about the case where the 2nd distribution part 27 consists of a several check valve, it may consist of an on-off valve similarly to the 1st distribution part 26. FIG.

Furthermore, during the cooling main operation or the heating main operation, the refrigerant flowing out from the

indoor units

30A and 30B performing the heating operation through the second distributor 27 flows in the second relay-side bypass pipe 29. Then, some or all of the refrigerant that has passed through the second relay-side bypass pipe 29 passes through the second inter-refrigerant heat exchanger 24 and the second distribution unit 27, and then performs the cooling operation of the indoor unit 30A. It flows to 30B. On the other hand, at the time of all heating operation, all of the refrigerant that has flowed out of the

indoor units

30A and 30B that are performing the heating operation via the second distribution unit 27 is supplied to the second repeater side flow rate regulator 25 and the first repeater side bypass pipe. It passes through 28 and flows into the second main pipe 3.

Since the first distribution unit 26 and the second distribution unit 27 are connected to the two

indoor units

30A and 30B, the first distribution unit 26 is provided with two sets of on-off valves and check valves. However, the number corresponding to the number of installed

indoor units

30A and 30B is installed.

[

Indoor units

30A, 30B]
Each of the

indoor units

30A and 30B is connected to the repeater 20 in parallel with each other and includes a use side heat exchanger 31 and a use side flow rate regulator 32 connected in series to the use side heat exchanger 31. is doing. In FIG. 1, each of the

indoor units

30A and 30B is illustrated as an example in which a plurality of usage-side heat exchangers 31 and usage-side flow rate regulators 32 are connected in parallel. What is necessary is just to have the use side heat exchanger 31 and the use side flow regulator 32 more than a group.

The use-side heat exchanger 31 exchanges heat between air blown from an indoor fan such as a fan (not shown) and the refrigerant supplied from the relay machine 20 and supplies air to the indoor space for cooling or cooling. Produce air. The usage-side flow rate regulator 32 is configured such that the opening of an electronic expansion valve or the like can be variably controlled. For example, the usage-side heat exchanger 31 is decompressed by expanding the refrigerant supplied from the relay unit 20 during the cooling operation. To supply. The opening degree of the use side flow rate regulator 32 is controlled by the control device 60.

[Control device 60]
The operation of the air conditioner 1 described above is controlled by the control device 60. The control device 60 includes, for example, a microcomputer, a computer, and the like. For example, determination processing based on signals transmitted from various detectors (sensors) provided inside and outside the air conditioner and each device (means) of the air conditioner 1. Etc. And the control apparatus 60 operates each apparatus based on a judgment result, and carries out overall control of the air conditioning apparatus 1 whole operation | movement, such as the heat source machine 10, the relay machine 20, and several indoor unit 30A, 30B. 1 illustrates a case where one control device 60 is provided separately and independently from the heat source device 10 or the like, but is not limited to this, and for example, the heat source device 10, the relay device 20, or a plurality of the devices. The

indoor units

30A and 30B may be built in, or the functions of the control device 60 may be distributed among the devices.

The control device 60 controls the operation of the entire air conditioner 1 based on information detected by various sensors. That is, the heat source device 10 is provided between the compressor outlet temperature detection unit 51 including a thermistor or the like that detects the temperature of the refrigerant discharged from the compressor, and the compressor 11 and the flow path switch 12. A high pressure detection unit 52 that detects the ambient temperature, an outside air temperature detection unit 53 that is provided in the heat source unit 10 to detect outside air, and a suction side pressure (low pressure) of refrigerant flowing into the accumulator 14 (suction side of the compressor 11). And a suction-side pressure detection unit 54 for detection. And the control apparatus 60 controls various apparatuses based on the information from various sensors so that it may mention later.

The relay 20 includes a first relay-side pressure detector 55 that detects the pressure of the refrigerant flowing between the first inter-refrigerant heat exchanger 22 and the first relay-side flow rate regulator 23, and a first relay. The second relay-side pressure detector 56 that detects the pressure of the refrigerant flowing between the machine-side flow rate regulator 23 and the second inter-refrigerant heat exchanger 24, and the first inter-refrigerant heat exchanger 22 to the first main pipe 2. From the temperature detector 57 that detects the temperature of the flowing refrigerant and the outlet of the second inter-refrigerant heat exchanger 24, that is, from the thermistor that detects the intermediate temperature of the refrigerant that flows downstream of the second inter-refrigerant heat exchanger 24, for example. And an intermediate temperature detector 58. Then, the control device 60 determines the difference between the first repeater side pressure detected by the first repeater side pressure detector 55 and the second repeater side pressure detected by the second repeater side pressure detector 56. Is controlled to become the target repeater side pressure.

The compressor outlet temperature detector 51, the high pressure detector 52, the outside air temperature detector 53, the suction side pressure detector 54, the first repeater side pressure detector 55, the second repeater side pressure detector 56, the temperature Various sensors such as the detection unit 57 and the intermediate temperature detection unit 58 may transmit the measurement results as they are to the control device 60, or the measurement results accumulated after the accumulation of the measurement results for a certain period of time may be transmitted at predetermined intervals. May be transmitted.

As described above, the air-conditioning apparatus 1 has four forms of a cooling only operation, a heating only operation, and a cooling / heating simultaneous operation (cooling main operation and heating main operation) by opening and closing the flow path switch 12 and the first distribution unit 26. (Mode) can be operated. The heat source side heat exchanger 13 functions as a condenser during the cooling only operation and the cooling main operation, and functions as an evaporator during the heating only operation and the heating main operation. Hereinafter, an operation example of the air-conditioning apparatus 1 and the flow of the refrigerant during the simultaneous cooling and heating operation (cooling main operation and heating main operation) will be described.

[Cooling operation]
FIG. 2 is a refrigerant circuit diagram illustrating a refrigerant flow when the cooling-heating simultaneous operation mainly performed by the cooling is performed in the air-conditioning apparatus of FIG. In FIG. 2, the case where the indoor unit 30 </ b> A performs the heating operation and the indoor unit 30 </ b> B performs the cooling / heating simultaneous operation in which the cooling load is higher than the heating load is performed. In FIG. 2, the flow of the refrigerant is indicated by an arrow, and among the check valve and the on-off valve, a portion where the refrigerant does not flow is indicated by black, and a portion where the refrigerant flows is indicated by white. In the cooling main operation of FIG. 2, the control device 60 opens the heating on-off valve 26a on the side of the indoor unit 30A that performs the heating operation, and closes the cooling on-off valve 26b. Further, the control device 60 closes the heating on-off valve 26a of the indoor unit 30B that performs the cooling operation, and opens the cooling on-off valve 26b.

The high-temperature and high-pressure gas refrigerant compressed and discharged in the compressor 11 flows into the heat source side heat exchanger 13 through the flow path switch 12. The high-temperature and high-pressure gas refrigerant exchanges heat with a heat source medium such as air in the heat source side heat exchanger 13, and the high-temperature and high-pressure gas refrigerant subjected to heat exchange becomes a high-temperature and high-pressure refrigerant in a gas-liquid two-phase state. The high-temperature and high-pressure refrigerant in the gas-liquid two-phase state passes through the second main pipe 3 through the check valve 15 a and is supplied to the relay-side gas-liquid separator 21 of the relay machine 20. Since the first main pipe 2 has a low pressure and the second main pipe 3 has a high pressure, the refrigerant flows to the check valve 15a and the check valve 15b due to the pressure difference between the two, and the refrigerant flows to the check valve 15c. Not distributed.

In the relay-side gas-liquid separator 21, the gas-liquid two-phase high-temperature and high-pressure refrigerant is separated into a gaseous refrigerant and a liquid refrigerant, and the separated gaseous refrigerant flows into the first distribution unit 26. The gaseous refrigerant that has flowed into the first distribution unit 26 is supplied to the indoor unit 30B in which the heating operation is set via the heating on-off valve 26a. In the use side heat exchanger 31 of the indoor unit 30B, the refrigerant exchanges heat with a use medium such as air to perform heating, and the supplied gaseous refrigerant condenses and liquefies. Thereafter, the liquid refrigerant condensed and liquefied by the use side heat exchanger 31 is reduced in pressure by the use side flow rate regulator 32 to become an intermediate pressure refrigerant that is an intermediate pressure between the high pressure and the low pressure. The refrigerant that has reached the intermediate pressure flows into the second distributor 27. The refrigerant flowing into the second distribution unit 27 passes through the heating check valve 27a side and flows into the second inter-refrigerant heat exchanger 24 through the second relay bypass pipe.

On the other hand, the liquid refrigerant separated by the relay-side gas-liquid separator 21 flows through the first inter-refrigerant heat exchanger 22 and the first relay-side flow rate adjuster 23, and merges with the refrigerant flowing out from the indoor unit 30A. The merged refrigerant flows into the second distribution unit 27 and flows into the indoor unit 30B from the cooling check valve 27b on the indoor unit 30B side. The liquid refrigerant that has flowed into the indoor unit 30B is supplied to the use-side heat exchanger 31 of the indoor unit 30A in a state where the refrigerant is decompressed to a low pressure using the use-side flow rate regulator 32. The liquid refrigerant supplied to the use side heat exchanger 31 is evaporated and gasified by exchanging heat with a use medium such as air.

The gasified refrigerant flows into the first distributor 26 through the second branch pipe 5 and flows into the heat source apparatus 10 from the cooling on-off valve 26b through the second main pipe 3. The gas refrigerant flows into the check valve 15 b that is lower in pressure than the check valve 16, and is sucked into the compressor 11 through the flow path switch 12 and the accumulator 14. With such an operation, a refrigeration cycle is formed and a cooling main operation is performed.

Here, the flow of the refrigerant in the first inter-refrigerant heat exchanger 22 and the second inter-refrigerant heat exchanger 24 will be described. The refrigerant branched from the second inter-refrigerant heat exchanger 24 to the first repeater-side bypass pipe 28 passes through the second repeater-side flow rate regulator 25, and the second inter-refrigerant heat exchanger 24, the first inter-refrigerant heat. In the exchanger 22, the refrigerant flowing from the relay-side gas-liquid separator 21 is supercooled and flows to the first main pipe 2. At this time, the liquid refrigerant that has flowed into the second relay-side flow rate regulator 25 is depressurized to a low pressure, and the evaporation temperature is lowered. The liquid refrigerant whose evaporation temperature has decreased flows into the second inter-refrigerant heat exchanger 24 via the first relay-side bypass pipe 28. In the second inter-refrigerant heat exchanger 24, heat is exchanged with the liquid refrigerant supplied from the first relay-side flow rate regulator 23 to become a gas-liquid two-phase refrigerant, which flows into the first inter-refrigerant heat exchanger 22. .

In the first inter-refrigerant heat exchanger 22, heat exchange with the high-temperature and high-pressure liquid refrigerant supplied from the relay-side gas-liquid separator 21 results in a gas refrigerant that flows into the first main pipe 2. When the opening degree of the second repeater side flow rate regulator 25 is large and the amount of refrigerant (refrigerant used for supercooling) flowing through the first repeater side bypass pipe 28 increases, the amount of refrigerant that is not evaporated increases too much. For this reason, the control device 60 outputs the outlet of the first repeater-side flow rate regulator 23 so that the pressure difference between the first repeater-side pressure detector 55 and the second repeater-side pressure detector 56 becomes a predetermined value. The superheat degree of the refrigerant at the second relay machine side flow controller 25 is controlled. Thus, the supercooled refrigerant flows to the second distribution unit 27 side, thereby reducing the enthalpy on the refrigerant inlet side (here, the first branch pipe 4 side), and in the utilization side heat exchanger 31, The amount of heat exchange with can be increased.

[Heating-based operation]
FIG. 3 is a refrigerant circuit diagram illustrating the flow of refrigerant when the heating / cooling simultaneous heating / cooling simultaneous operation is performed in the air conditioning apparatus of FIG. 1. In addition, in FIG. 3, the case where the indoor unit 30A performs the heating operation and the indoor unit 30B performs the cooling / heating simultaneous operation in which the cooling load is higher than the heating load is performed. Moreover, in FIG. 2, the site | part which a refrigerant | coolant does not distribute | circulate among the check valve and the on-off valve is shown in black, and the part through which the refrigerant circulates is shown in white. In the cooling main operation of FIG. 2, the control device 60 opens the heating on-off valve 26a and closes the cooling on-off valve 26b on the indoor unit 30A side. Further, the control device 60 closes the heating on-off valve 26a on the indoor unit 30B side and opens the cooling on-off valve 26b. Furthermore, in FIG. 3, among the capacity control valves 41, the upper control valve 41a is closed and the lower control valve 41b is opened, so that no refrigerant flows through the upper heat exchange section 13a. It has become.

First, the high-temperature and high-pressure gas refrigerant compressed and discharged in the compressor 11 passes through the second main pipe 3 via the flow path switch 12 and the check valve 15c, and then the relay-side gas-liquid separator of the relay 20 21. At this time, the first main pipe 2 has a low pressure, and the second main pipe 3 has a high pressure. Therefore, due to the pressure difference between them, the refrigerant flows through the check valve 15c, and the refrigerant does not flow through the check valve 15a and the check valve 15b.

The high-temperature and high-pressure gas refrigerant that has flowed into the relay-side gas-liquid separator 21 is supplied to the first distributor 26 via the gas-phase pipe 21a. The gas refrigerant supplied to the first distribution unit 26 flows into the heating on-off valve 26a on the indoor unit 30A side, and is supplied to the indoor unit 30A in which the heating operation is set through the second branch pipe 5.

In the indoor unit 30A, the refrigerant exchanges heat with a utilization medium such as air by the utilization side heat exchanger 31, and the supplied gas refrigerant is condensed and liquefied. At this time, the opening degree of the use side flow rate regulator 32 is controlled based on the degree of supercooling at the outlet of the use side heat exchanger 31. The liquid refrigerant condensed and liquefied in the usage-side heat exchanger 31 is reduced in pressure in the usage-side flow rate regulator 32 to become an intermediate-pressure liquid refrigerant that is an intermediate pressure between the high pressure and the low pressure. The intermediate-pressure liquid refrigerant flows into the second distribution unit 27.

The liquid refrigerant that has flowed into the second distributor 27 passes through the second repeater-side bypass pipe 29 and merges with the liquid refrigerant separated in the repeater-side gas-liquid separator 21. Thereafter, the liquid refrigerant passes through the second inter-refrigerant heat exchanger 24 and flows into the second distribution unit 27. At this time, the liquid refrigerant passes through the second inter-refrigerant heat exchanger 24, then branches to the first relay-side bypass pipe 28, and flows into the second inter-refrigerant heat exchanger 24 again. In the second inter-refrigerant heat exchanger 24, heat exchange is performed between the intermediate-pressure liquid refrigerant and the low-pressure liquid refrigerant, and the low-pressure liquid refrigerant has a low evaporation temperature, and thus flows into the first main pipe 2 as a gas refrigerant. .

The intermediate-pressure liquid refrigerant that has flowed into the second distributor 27 flows into the indoor unit 30B via the cooling check valve 27b connected to the indoor unit 30B. The liquid refrigerant that has flowed into the indoor unit 30B is reduced in pressure to a low pressure by using the use-side flow rate regulator 32 controlled according to the degree of superheat at the outlet of the use-side heat exchanger 31 of the indoor unit 30B, and the evaporation temperature is low. Then, it is supplied to the use side heat exchanger 31. In the use-side heat exchanger 31, the supplied liquid refrigerant having a low evaporation temperature is evaporated and gasified by exchanging heat with a use medium such as air. The refrigerant that has become the gas refrigerant passes through the first main pipe 2 and flows into the first distribution unit 26. The gas refrigerant that has flowed into the first distributor 26 passes through the cooling on-off valve 26b connected to the indoor unit 30B and flows into the first main pipe 2.

The gas refrigerant that has flowed into the first main pipe 2 flows into the heat source side gas-liquid separator 42 having a lower pressure than the check valve 15b. Then, the gas refrigerant branches into the first branch pipe 43a, the second branch pipe 43b, and the third branch pipe 43c in the heat source side gas-liquid separator 42. The refrigerant branched to the first branch pipe 43a passes through the check valve 16 and the lower control valve 41b, flows into the lower heat exchange section 13b, and performs heat exchange. The refrigerant branched to the second branch pipe 43b flows into the lower heat exchange section 13b through the flow rate control device 44 and heat exchange is performed. When the on-off valve 45 is opened, the gas refrigerant branched to the third branch pipe 43 c flows into the accumulator 14. Thereafter, the heat-exchanged refrigerant flows into the accumulator 14 via the check valve 47 and the flow path switch 12. Next, the air is sucked into the compressor 11 through the accumulator 14. With such an operation, a refrigeration cycle is formed, and a heating main operation is performed.

In addition, although the cooling main operation of FIG. 2 and the heating main operation of FIG. 3 are illustrated as the operation modes of the air conditioner 1, all the

indoor units

30A and 30B perform the cooling operation and all the indoor operations. The all-heating operation in which the machine 30B performs the heating operation can also be performed. In the case of the cooling only operation, the refrigerant flow path in the heat source apparatus 10 is the same as the refrigerant flow path of FIG. However, in the relay machine 20, the refrigerant does not flow from the indoor unit 30A side in the heating operation to the indoor unit 30B side in the cooling operation as shown in FIG. It will flow to both

indoor units

30A and 30B. Further, in the case of the heating only operation, the refrigerant flow path in the heat source device 10 is the same as the refrigerant flow path of FIG. However, in the relay machine 20, the refrigerant does not flow from the indoor unit 30A side in the heating operation to the indoor unit 30B side in the cooling operation as shown in FIG. It flows to both

indoor units

30A and 30B.

Here, the control device 60 has a function of controlling the operations of the capacity control valve 41, the flow rate control device 44, and the on-off valve 45 of the heat source unit 10 according to the operation mode. Specifically, the control device 60 opens the flow rate control device 44 so that the ratio of the refrigerant flow rate flowing through the upper stage heat exchange unit 13a and the lower stage heat exchange unit 13b becomes a set ratio during the heating operation. Control the degree. For example, the set refrigerant flow rate ratio of the upper stage heat exchange section 13a and the lower stage heat exchange section 13b is upper stage heat exchange section 13a: lower stage heat exchange section 13b = 8.5 to 9.5: 5. At this time, the control device 60 stores in advance a set opening degree that can be a setting ratio, and the control device 60 sets the opening degree of the flow rate control device 44 when the heating operation is performed. Fix in degrees. Thereby, high heating performance can be maintained as the air conditioning apparatus 1 as a whole.

FIG. 4 is a graph showing the relationship between the flow rate regulator and the heating performance when the all-heating operation is performed in the air conditioner of FIG. As shown in FIG. 4, when the flow rate control device 44 is set to a predetermined opening VPp or more in the heating only operation in which the heat source side heat exchanger 13 functions as an evaporator, the refrigerant flows into the lower stage heat exchange portion 13 b. The amount increases. For this reason, the amount of heat exchange in the lower stage side heat exchanging portion 13b is insufficient, and liquid back is made to the accumulator 14, whereby the suction side pressure of the compressor 11 is lowered and the heating performance is lowered. Therefore, during the heating only operation, the opening degree of the flow rate control device 44 is fixed to the set opening degree so that the amount of refrigerant flowing through the lower heat exchange section 13b satisfies the set ratio described above. Then, the flow rate of the refrigerant flowing through the lower stage side heat exchange unit 13b is limited, and as a result, the refrigerant flow rate to the upper stage side heat exchange unit 13a is increased. Thereby, optimal refrigerant | coolant distribution can be performed to the upper stage side heat exchange part 13a and the lower stage side heat exchange part 13b.

In addition, the control device 60 performs the operation ratio between the cooling operation and the heating operation in the plurality of indoor units, the outside air temperature detected by the outside air temperature detection unit 53, and the intake air during the simultaneous cooling and heating operation illustrated in FIGS. Based on the suction side pressure detected by the side pressure detector 54, the opening degree of the flow rate control device 44 is controlled.

FIG. 5 is a flowchart showing an example of the operation of the flow control device during the simultaneous cooling and heating operation of the air conditioner of FIGS. As shown in FIG. 5, specifically, the control device 60 performs control so that the opening degree of the flow control device 44 is fixed to a preset initial opening degree at the start of the simultaneous cooling and heating operation (step ST1). . Thereafter, the control device 60 detects whether the heating load is equal to or higher than the cooling load, whether the outside air temperature detected by the outside air temperature detection unit 53 is lower than an outside air temperature threshold (for example, 5 deg), or is detected by the suction side pressure detection unit 54. It is determined whether the suction side pressure is smaller than a pressure threshold (for example, 0.7 MPa) (steps ST2 to ST4). Further, it is determined whether the intermediate temperature detected by the intermediate temperature detection unit 58 is smaller than an intermediate temperature threshold (for example, 4 deg) (step ST5). Note that the order of determination in steps ST2 to ST5 need not be in the order shown in FIG. 5, and may be in any order.

When all the conditions of steps ST2 to ST5 are satisfied, the evaporating temperature of the indoor unit 30B that is performing the cooling operation becomes a predetermined value or less, and the cooling operation cannot be continued. Therefore, the control device 60 releases the fixed opening of each flow control device 44 and controls the opening of the flow control device 44 variably. At this time, the flow control device 44 is adjusted so that the evaporation temperature of the indoor unit 30B performing the cooling operation does not become a predetermined value or less. The evaporating temperature is detected by an evaporating temperature detecting unit 59 that detects the temperature of the refrigerant flowing in the use side heat exchanger 31. Thereby, the simultaneous cooling and heating operation of the

indoor units

30A and 30B can be maintained. That is, when the cooling main operation (heating load <cooling load) is performed, the opening degree of the flow rate control device 44 is fixed to the set opening degree, and when the heating main operation (heating load> cooling load) is performed. When the predetermined condition is satisfied, the opening degree of the flow control device 44 is variably controlled.

1 to 3 has a function of controlling the operation of the on-off valve 45 based on the capacity of the heat source side heat exchanger 13 and the degree of superheat of the compressor outlet during the cooling only operation. . Specifically, the control device 60 calculates the degree of superheat of the compressor outlet based on the compressor outlet temperature detected by the compressor outlet temperature detector 51 and the high pressure detected by the high pressure detector 52. . When the lower control valve 41b of the capacity control valve 41 is open and the outlet superheat degree TdSH of the compressor is equal to or higher than the set outlet superheat degree SHref (for example, 20 deg), the control device 60 opens the on-off valve 45. Open.

FIG. 6 is a flowchart showing an operation example of the on-off valve when the air-conditioning apparatus of FIG. 1 is performing the cooling operation. It is assumed that the opening / closing valve 45 is closed at the start of the cooling only operation. As shown in FIG. 6, at the start of the cooling only operation, the control device 60 determines whether or not the lower control valve 41b is closed (step ST11). When the lower control valve 41b is closed (YES in step ST11), control is performed so that the flow rate control device 44 is fixed at a predetermined opening (step ST12). Then, a predetermined amount of refrigerant flows from the first branch pipe side into the lower heat exchange section 13b, and the refrigerant present in the lower heat exchange section 13b is returned to the accumulator 14.

On the other hand, if the lower control valve 41b is open (NO in step ST11), it is determined whether the outlet superheat degree TdSH of the compressor 11 is equal to or higher than the set outlet superheat degree SHref (step ST14). When the outlet superheat degree TdSH is equal to or higher than the set outlet superheat degree SHref (YES in step ST14), the on-off valve 45 is opened (step ST15). Then, a part of the refrigerant flowing from the relay machine 20 toward the accumulator 14 passes through the third branch pipe 43c, the heat source side gas-liquid separator 42, the second branch pipe 43b, and the flow rate control device 44, and the lower stage side heat exchange section 13b. Flow into. Thereby, the low-pressure pressure loss by piping can be reduced, the evaporation temperature of

indoor unit

30A, 30B (evaporator) rises, and it can maintain high cooling performance. On the other hand, when the outlet superheat degree TdSH is less than the set outlet superheat degree SHref, the on-off valve 45 is closed (step ST16). Thereby, when the lower control valve 41b is opened, it is possible to prevent the refrigerant from expanding even if the gas refrigerant flows into the lower heat exchange section 13b.

According to the above embodiment, the heat source side heat exchanger 13 is divided into the upper stage side heat exchanging part 13a and the lower stage side heat exchanging part 13b, and the flow rate capable of adjusting the amount of refrigerant flowing into the lower stage side heat exchanging part 13b. By providing the control device 44 and narrowing the flow rate control device 44, a large amount of refrigerant can be flowed to the upper stage heat exchange section 13a.

For example, when the heat exchanger that exchanges heat with air has a structure that blows wind upward (so-called top flow), the wind speed that passes through the upper heat exchange section 13a is higher than the wind speed that passes through the lower heat exchange section 13b. large. Therefore, by reducing the opening degree of the flow control device 44, the amount of refrigerant flowing into the lower heat exchange section 13b is regulated, and as a result, the amount of refrigerant flowing into the upper heat exchange section 13a can be increased. As described above, the heat source side heat exchanger 13 can perform heat exchange evenly by flowing the refrigerant amount to the upper stage side heat exchanging part 13a and the lower stage side heat exchanging part 13b appropriately according to the wind speed. Performance can be improved.

In particular, the flow rate control device 44 is not connected to the upper stage heat exchange section 13a, but is connected to the lower stage heat exchange section 13b, thereby reliably increasing the refrigerant flow rate to the upper stage heat exchange section 13a. Can do. That is, when the flow control device 44 is connected to the upper stage heat exchanging portion 13a, the refrigerant tends to be biased downward due to gravity. Therefore, by reducing the opening degree of the flow control device 44, the upper stage heat exchanging portion is reduced. Even if the refrigerant flow rate to 13a can be reduced, it is difficult to increase the refrigerant flow rate to the upper heat exchange section 13a by increasing the opening degree of the flow rate control device 44. In particular, in the case of a heating flow path in which the heat source side heat exchanger 13 is an evaporator, the liquid refrigerant flows into the heat source side heat exchanger 13, and thus the tendency becomes remarkable. Therefore, by connecting the flow rate control device 44 to the upper stage heat exchange unit 13a, the refrigerant flow rate to the upper stage side heat exchange unit 13a can be reliably increased if the opening degree of the flow rate control device 44 is reduced.

That is, generally, a heat exchanger using a flat tube has a smaller cross-sectional area of the heat transfer tube than a circular tube heat exchanger. For this reason, the flow velocity inside a heat exchanger tube increases rather than a circular tube heat exchanger, and pressure loss increases in connection with it. An increase in pressure loss decreases the suction density of the compressor, leading to a decrease in capacity and a decrease in efficiency. Therefore, in a heat exchanger using a flat tube, it is necessary to increase the number of passes of the heat exchanger.

On the other hand, in order to increase the heat transfer area in a limited unit space, when the heat exchanger is composed of a plurality of rows, the pressure loss is reduced if the necessary length of the heat exchanger is ensured. Therefore, since it is better to make the product length of the heat transfer tubes as short as possible, it is conceivable to connect the lead pipes between the rows. However, when lead pipes are used, the path shape becomes complicated in order to prevent interference between the lead pipes. For example, problems such as brazing such that the header pipe connected to the lead pipe becomes larger than the depth of the heat exchanger, such as brazing, cannot be automated, resulting in poor heat exchanger productivity and increased cost.

Further, when the heat source side heat exchanger has a configuration in which one end of the flat tubes arranged in the vertical direction is connected to the first header collecting pipe and the other end is connected to the second header collecting pipe 70, the heat source side heat exchanger has When functioning as a condenser, only the refrigerant supplied to some of the heat exchanger parts flows into each communication space in the second header collecting pipe in order to reduce the difference in refrigerant flow rate among the plurality of heat exchange parts. Let Further, in order to reduce the pressure loss in the evaporator, it is conceivable that the number of times of changing the flow direction in the second header collecting pipe is set to only one.

However, when the heat source side heat exchanger functions as a condenser, since the refrigerant flows into the plurality of spaces, the portion to be filled with the liquid refrigerant becomes small. If the amount of the refrigerant is small, it is easy to be affected by the header, the refrigerant does not flow smoothly, and the performance of the heat exchanger deteriorates. Furthermore, a communication space by a plurality of partition plates for partitioning the header collecting pipe of the flat tube heat exchanger is required, and the number of pipes to be connected increases. For this reason, it becomes difficult to handle the piping, the structure becomes complicated, and the number of brazing points increases, so that the productivity is deteriorated and the cost is increased.

On the other hand, by providing the flow control device 44 connected to the lower heat exchange section 13b as in the above embodiment, the structure of the heat source heat exchanger is not complicated as in the prior art. Optimal refrigerant distribution can be performed for the upper stage heat exchange section 13a and the lower stage heat exchange section 13b. As a result, productivity can be improved and cost can be reduced.

In addition, when the control device 60 controls the operation of the flow rate control device 44 according to various operation modes, there are a plurality of use side heat exchangers 31 that are performing the cooling operation or the heating operation during the simultaneous cooling and heating operation. Even so, stable control can be performed at low cost and without performance degradation. Therefore, comfort and productivity can be maintained at the same time.

Furthermore, when the control device 60 controls the opening degree of the flow rate control device 44 so that the ratio of the refrigerant flow rate flowing through the upper stage side heat exchange unit 13a and the lower stage side heat exchange unit 13b during the heating operation becomes a set ratio, Since the flow rate of the refrigerant flowing into the lower stage heat exchange unit 13b can be regulated and the flow rate of the refrigerant flowing into the upper stage heat exchange unit 13a can be increased, optimal refrigerant distribution can be performed.

Further, as shown in FIG. 5, the control device 60 is based on the operation ratio of the cooling operation and the heating operation at the time of the simultaneous cooling and heating operation of the plurality of

indoor units

30A and 30B, the outside air temperature, and the suction side pressure. When the opening degree of the flow rate control device 44 is controlled and the opening degree of the flow rate control device 44 is released, the flow rate control device 44 is set so that the evaporation temperature of the use side heat exchanger 31 is equal to or higher than the set evaporation temperature. When the opening degree is controlled, it is possible to suppress the evaporation temperature of the indoor unit 30B that is performing the cooling operation during the cooling and heating simultaneous operation from being equal to or lower than a predetermined value, thereby preventing the cooling capacity from being lowered.

Further, as shown in FIG. 6, the control device 60 controls the operation of the on-off valve 45 based on the capacity of the heat source side heat exchanger 13 and the outlet superheat degree TdSH during the cooling operation. The heat source side heat exchanger 13 can perform heat exchange evenly by flowing the refrigerant in the lower stage side heat exchanging portion 13b appropriately according to the wind speed, and the performance of the heat source side heat exchanger 13 can be improved.

The embodiment of the present invention is not limited to the above embodiment, and various changes can be made. For example, in the above-described embodiment, an example in which there is one heat source unit 10 and two

indoor units

30A and 30B will be described. However, the present invention is not limited to this, and for example, a plurality of indoor units are two or more units. It may be the case. Further, for example, a plurality of heat source devices 10 may be used, or a plurality of relay devices 20 may be used.

Furthermore, in FIG. 4, although the case where the opening degree of the flow control device 44 is fixed to the set opening degree is illustrated, the opening degree is adjusted in accordance with the wind speed in the upper stage side heat exchange unit 13a and the lower stage side heat exchange unit 13b. It may be variably controlled. In this case, for example, an upper temperature sensor and a lower temperature sensor for detecting the temperature of the refrigerant flowing through the upper heat exchange unit 13a and the lower heat exchange unit 13b are provided, and the control device 60 is detected by the upper temperature sensor and the lower temperature sensor. The opening speed of the flow control device 44 may be controlled by detecting the wind speed (heat exchange amount) based on the detected temperature.

DESCRIPTION OF SYMBOLS 1 Air conditioner, 2nd 1st main pipe, 3rd 2nd main pipe, 4th 1st branch pipe, 5th 2nd branch pipe, 10 heat source machine, 11 compressor, 12 flow path switcher, 13 heat source side heat exchanger, 13a upper stage Side heat exchange section, 13b Lower stage heat exchange section, 14 Accumulator, 15 Flow path forming section, 15a, 15b, 15c, 16 Check valve, 20 Relay machine, 21 Relay machine side gas-liquid separator, 21a Gas phase piping, 21b Liquid phase piping, 22 1st inter-refrigerant heat exchanger, 23 2nd relay side flow regulator, 24 2nd inter-refrigerant heat exchanger, 25 2nd relay side flow regulator, 26 1st distribution part, 26a Heating on / off valve, 26b Cooling on / off valve, 27 Second distributor, 27a Heating check valve, 27b Air conditioning check valve, 28 First relay side bypass piping, 29 Second relay side bypass piping, 30A , 30B room , 31 User side heat exchanger, 32 User side flow regulator, 41 Capacity control valve, 41a Upper stage control valve, 41b Lower stage control valve, 41x Check valve, 42 Heat source side gas-liquid separator, 43a First branch pipe , 43b 2nd branch piping, 43c 3rd branch piping, 44 flow control device, 45 open / close valve, 46 connection piping, 47 check valve, 51 compressor outlet temperature detection unit, 52 high pressure detection unit, 53 outside air temperature detection unit , 54 suction side pressure detection unit, 55 first relay side pressure detector, 56 second relay side pressure detector, 57 temperature detection unit, 58 intermediate temperature detection unit, 59 evaporation temperature detection unit, 60 control device, SHref Set outlet superheat, TdSH outlet superheat, VPp predetermined opening.

Claims

A compressor that compresses and discharges the refrigerant, and a heat source machine having a heat source side heat exchanger that exchanges heat between the refrigerant discharged from the compressor and the heat source medium,
A plurality of indoor units having a use side heat exchanger that performs heat exchange between the refrigerant and the use medium, and a heat source side flow rate regulator connected to the use side heat exchanger;
A relay that is connected between the heat source unit and the plurality of indoor units via a refrigerant pipe, and distributes the refrigerant flowing out of the heat source side heat exchanger to the plurality of indoor units,
The heat source side heat exchanger is connected to the compressor in parallel with each other, and includes an upper stage side heat exchange part and a lower stage side heat exchange part arranged in the vertical direction,
The heat source machine is
A capacity control valve for controlling the capacity of the heat source side heat exchanger by controlling the flow of refrigerant into the upper stage side heat exchange section and the lower stage side heat exchange section;
A heat source side gas-liquid separator that separates the refrigerant flowing from the relay into gas refrigerant and liquid refrigerant;
A first branch pipe for allowing the refrigerant flowing into the heat source side gas-liquid separator to flow into the capacity control valve;
A second branch pipe for allowing the refrigerant that has flowed into the heat source side gas-liquid separator to flow into the lower heat exchange section;
An air conditioner comprising: a flow rate control device that is provided in the second branch pipe and adjusts the flow rate of the refrigerant flowing into the lower heat exchange section via the second branch pipe.
A control device for controlling the operation of the heat source unit and the relay unit so as to perform the cooling and heating simultaneous operation in which the cooling operation and the heating operation are performed simultaneously;
The air conditioning apparatus according to claim 1, wherein the control device controls an opening degree of the flow control device according to an operation mode.
The control device controls an opening degree of the flow rate control device so that a ratio of a refrigerant flow rate flowing through the upper stage side heat exchange unit and the lower stage side heat exchange unit during a heating operation becomes a set ratio. Item 3. The air conditioner according to Item 2.
An outside air temperature detection unit that is provided in the heat source unit and detects an outside air temperature, and a pressure detection unit that is provided on the suction side of the compressor and detects the suction side pressure of the refrigerant flowing to the suction side of the compressor. ,
The control device includes an operation ratio between a cooling operation and a heating operation during simultaneous cooling and heating of the plurality of indoor units, the outside air temperature detected by the outside air temperature detection unit, and the pressure detected by the pressure detection unit. The air conditioner according to claim 2 or 3, wherein the opening degree of the flow rate control device is controlled based on the suction side pressure.
The control device fixes the opening of the flow control device to a set opening at the start of simultaneous cooling and heating operation, the heating load is larger than the cooling load, the outside air temperature is lower than the outside air temperature threshold, and the suction side The air conditioning apparatus according to claim 4, wherein when the pressure is smaller than a pressure threshold, the opening degree of the flow control device is released and the opening degree of the flow control device is variably controlled.
The control device controls the opening degree of the flow rate control device so that when the opening degree of the flow rate control device is released, the evaporation temperature of the use side heat exchanger becomes equal to or higher than a set evaporation temperature. The air conditioner according to claim 5.
The heat source machine is
A third branch pipe for allowing the gas refrigerant separated by the heat source side gas-liquid separator to flow into the suction side of the compressor;
7. An on-off valve provided in the third branch pipe and further configured to control the inflow of gas refrigerant from the heat source side gas-liquid separator to the suction side of the compressor. The air conditioning apparatus described.
A control device for controlling the opening / closing operation of the on-off valve;
The air conditioner according to claim 7, wherein the control device controls an operation of the on-off valve based on a capacity of the heat source side heat exchanger and a compressor outlet superheat degree during cooling operation.
The control device opens the on-off valve when the control valve on the lower heat exchange section side of the capacity control valve is open and the compressor outlet superheat is equal to or higher than the set outlet superheat The air conditioner according to claim 8.
The heat source side heat exchanger is
The cross-sectional shape has a shape with a rounded rectangle with a large aspect ratio,
A single-row flat tube heat exchanger having a flat tube through which a refrigerant flows and a plurality of plate-like fins into which the flat tube is inserted and joined in a direction perpendicular to the flat tube has two or less rows in the thickness direction. The air conditioner according to any one of claims 1 to 9, wherein the air conditioner is combined with each other.