JP3538936B2 - Refrigerant refrigerant recovery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering refrigerant in a refrigerating apparatus having a plurality of heat source units, and more particularly to a method for recovering refrigerant when an abnormality occurs.

[0002]

2. Description of the Related Art Conventionally, an air conditioner as a refrigerating apparatus includes a compressor, a four-way switching valve, an outdoor heat exchanger, and an outdoor electric expansion valve, as disclosed in WO94 / 19654. The two outdoor units provided are connected in parallel to the main liquid line and the main gas line, while the plural indoor units provided with the indoor electric expansion valve and the indoor heat exchanger are connected to the main liquid line and the main liquid line. Some are configured to be connected in parallel to a gas line.

[0003] During the cooling operation, the refrigerant discharged from the compressor of each outdoor unit condenses in the outdoor heat exchanger and merges in the main liquid line.
The pressure is reduced by the indoor expansion valve, evaporated by the indoor heat exchanger, diverted from the main gas line to each outdoor unit, and returned to the compressor of each outdoor unit.

[0004] On the other hand, during the heating operation, the refrigerant discharged from the compressor of each outdoor unit merges in the main gas line, is condensed in the indoor heat exchanger, and is diverted from the main liquid line to each outdoor unit. Thereafter, the refrigerant is reduced in pressure by the outdoor electric expansion valve of each outdoor unit, evaporates in the outdoor heat exchanger, and returns to the compressor.

[0005]

In the above-described air conditioner, since a plurality of outdoor units are provided, a large amount of refrigerant is provided. On the other hand, when maintenance is required, for example, when one outdoor unit breaks down, a large amount of refrigerant cannot be collected only by the receiver, so that the refrigerant must be released to the atmosphere, which has a problem that waste is covered. Was.

The present invention has been made in view of the above circumstances, and has as its object to enable maintenance of a heat source unit without releasing a refrigerant to the atmosphere.

[0007]

Means for Solving the Problems In order to achieve the above object, means taken by the present invention makes it possible to recover a refrigerant from one heat source unit.

Specifically, as shown in FIG. 1, the means according to the first aspect of the present invention comprises a compression mechanism (21), one end of which is connected to the compression mechanism (21) and the other end of which is branched. Heat source side heat exchanger (23) to which liquid lines (5L-A, 5L-B, ...) are connected
The compression mechanism (21) has a branch gas line (5G-
A, 5G-B, ...) connected to multiple heat source units (2A, 2G
B, ...) are provided. The heat source units (2A, 2B, ...) are connected in parallel via branch liquid lines (5L-A, 5L-B, ...) and branch gas lines (5G-A, 5G-B, ...). Main liquid line (4L) and main gas line (4L)
G) is provided. Further, a plurality of use units (3A) having an expansion mechanism (32) and a use side heat exchanger (31) and connected in parallel to the main liquid line (4L) and the main gas line (4G). , 3B, ...) are provided.
In addition, the branch liquid line (5L-A, 5L-B, ...) and the branch gas line (5G-A, 5G) of each heat source unit (2A, 2B, ...)
-B, ...) are always closed valves (OV, OV, ...)
It is assumed that the refrigeration system is provided with.

When the first heat source unit (2A) is abnormal, first, the closing valve (OV) of the branch liquid line (5L-A) in the abnormal heat source unit (2A) is closed. Subsequently, the refrigerant recovery means (81) is connected to another heat source unit (2B,...)
Is operated in the cooling operation cycle and the abnormal heat source unit (2
Collect the refrigerant in A). Then, branch gas line (5G-
A) Close the shut-off valve (OV) of the abnormal heat source unit (2
A) The low pressure refrigerant pressure drops below the outdoor air temperature equivalent pressure
Then , the refrigerant collection ends.

[0010] The means adopted by the invention according to claim 2 is the refrigerant recovery means (81) according to the invention of claim 1 described above.
When the suction refrigerant temperature of the compression mechanism (21) in the normal heat source unit (2B) or the saturation temperature corresponding to the evaporation pressure in the normal heat source unit (2B) is higher than the predetermined temperature with respect to the outside air temperature, While the air volume of the use side fan (31-F) is sequentially reduced, if the intake refrigerant temperature or the evaporation pressure equivalent saturation temperature of the compression mechanism (21) is lower than a predetermined temperature with respect to the outside air temperature, the use side heat exchanger ( An air volume changing means (82) for sequentially increasing the air volume of the use side fan (31-F) of 31) is provided.

Further, the means adopted by the invention according to claim 3 is the refrigerant recovery means (81) according to the invention according to claim 2 described above.
Is configured to control the degree of superheating of the expansion mechanism (32) of the utilization unit (3A, 3B,...) During refrigerant recovery.

Further, the means adopted by the invention according to claim 4 is the refrigerant recovery means (81) according to the invention of claim 1 described above.
A low air volume means (83) for setting the air volume of the usage side fan (31-F) of the usage side heat exchanger (31) to a constant low air volume when the refrigerant is recovered.

[0013]

According to the first aspect of the present invention,
If one heat source unit (2A) is abnormal,
Branch liquid line (5L) in the abnormal heat source unit (2A)
-A) Close the closing valve (OV). Subsequently, the refrigerant recovery means (81) connects the other heat source units (2B, ...) to the cooling operation system.
Operate the vehicle and collect the refrigerant of the abnormal heat source unit (2A). Then, the closing valve (OV) of the branch gas line (5G-A)
Closed, abnormal heat source unit (2A) low pressure refrigerant pressure
When the pressure falls below the outdoor air temperature equivalent pressure , the refrigerant recovery is terminated.

When the refrigerant is recovered by the refrigerant recovery means (81), the air volume changing means (82) is
If the suction refrigerant temperature or the evaporation pressure equivalent saturation temperature of the compression mechanism (21) in the normal heat source unit (2B) is equal to or higher than the predetermined temperature with respect to the outside air temperature, the use side fan (31) of the use side heat exchanger (31) -F), while the suction air temperature of the compression mechanism (21) or the saturation temperature corresponding to the evaporating pressure is lower than a predetermined temperature with respect to the outside air temperature, the use of the use-side heat exchanger (31). Increase the air volume of the side fan (31-F) sequentially.

In particular, in the invention according to claim 3, since the refrigerant recovery means (81) controls the degree of superheating of the expansion mechanism (32) of the use unit (3A, 3B,...), The use side fan (31) -
The lowering of the air flow in F) controls the opening degree of the expansion mechanism (32) to be small, and the air flow control ensures that the low-pressure refrigerant pressure is reduced.

On the other hand, in the invention according to claim 4, when the refrigerant is recovered by the refrigerant recovery means (81), the low air volume means (83)
Set the air volume of the usage side fan (31-F) of the usage side heat exchanger (31) to a constant low air volume. This low air volume control ensures that the low-pressure refrigerant pressure drops.

[0017]

According to the first aspect of the present invention,
Since the refrigerant is collected when the heat source unit (2A) of 1 is abnormal, the refrigerant is not released to the atmosphere.
Effective utilization of the refrigerant can be achieved.

Further, according to the second and fourth aspects of the present invention, since the flow rate of the use side fan (31-F) is reduced at the time of collecting the refrigerant, the pressure of the low-pressure refrigerant can be surely reduced. Therefore, the refrigerant can be quickly recovered.

In particular, according to the third aspect of the present invention, since the refrigerant recovery means (81) controls the degree of superheating of the expansion mechanism (32) of the use units (3A, 3B,...), The use-side fan Since the degree of opening of the expansion mechanism (32) is controlled to be small by the decrease in the air volume of (31-F), the low-pressure refrigerant pressure can be reliably reduced by the air volume control, and the refrigerant can be recovered more quickly. be able to.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

-Overall Configuration- As shown in FIG. 2, the air conditioner (10) as a refrigeration apparatus in the present embodiment has three outdoor units (2A, 2B,
2C) and three indoor units (3A, 3B, 3C) are connected in parallel to the main liquid line (4L) and the main gas line (4G), respectively.

Each of the outdoor units (2A, 2B, 2C) includes a compression mechanism (21), a four-way switching valve (22), and an outdoor fan (23-F).
Constitutes a heat source unit including an outdoor heat exchanger (23), which is a heat source side heat exchanger, and an outdoor electric expansion valve (24). The refrigerant pipe (25) is connected to one end of the outdoor heat exchanger (23) that is the gas side, and the branch liquid lines (5L-A, 5L-B, 5L-C) are connected to the other end that is the liquid side. Have been.

The gas-side refrigerant pipe (25) is switchably connected to the discharge side and the suction side of the compression mechanism (21) by a four-way switching valve (22), while the branch liquid line (5L-A , 5L-
B, 5L-C) is provided with the outdoor electric expansion valve (24) and is connected to the outdoor heat exchanger (23) and the main liquid line (4L). And each of the above branch liquid lines (5L-A, 5L-B,
A receiver (11) is provided at the connection between the main liquid line (4L) and the main liquid line (4L), and each of the branch liquid lines (5L-A, 5L-B, 5L-C) is connected by the receiver (11). Main liquid line (4L)
And are connected.

A branch gas line (5G-A, 5G-B, 5G-C) is connected to the compression mechanism (21) through a refrigerant pipe (25) and a four-way switching valve (22). Gas lines (5G-A, 5G
-B and 5G-C) are compressed by the four-way switching valve (22).
It is switchably connected to the suction side and discharge side of 1) and is connected to the main gas line (4G). The refrigerant pipe (25) between the suction side of the compression mechanism (21) and the four-way switching valve (22) is provided with an accumulator (26).

Of the three outdoor units (2A, 2B, 2C), the first outdoor unit (2A) constitutes a master unit, and the second outdoor unit (2B) and the third outdoor unit (2C) constitute slave units. The first outdoor unit (2A) is connected to the second outdoor unit (2A).
B) and the third outdoor unit (2C) are driven before the first outdoor unit (2A) and the second outdoor unit (2B) and the third outdoor unit (2C) are mainly composed of a compression mechanism ( The configuration of 21) is different.

That is, as shown in FIG. 3, the compression mechanism (21) of the first outdoor unit (2A) is a variable displacement type upstream compressor (COMP-1) whose capacity is controlled in multiple stages by inverter control. ) And a constant-capacity downstream compressor (COMP-2) controlled to two types of operation and stop are configured in a so-called twin type in which they are connected in parallel. On the other hand, the compression mechanism (21) of the second outdoor unit (2B) and the third outdoor unit (2C)
As shown in FIG. 4, each of the upstream compressor (COMP-1) and the downstream compressor (COMP-2) is constituted by a constant displacement compressor in which both operation and stop are controlled. The upstream compressor (COMP-1) and the downstream compressor (COMP-2) are configured in a so-called twin type in which they are connected in parallel. In each of the outdoor units (2A, 2B, 2C), the upstream compressor (COMP-1) is driven prior to the downstream compressor (COMP-2).

On the other hand, each indoor unit (3A, 3B, 3C)
An indoor heat exchanger (31), which is a use-side heat exchanger in which an indoor fan (31-F) is disposed in close proximity, and an indoor electric expansion valve (32), which is an expansion mechanism, constitute a use unit. . The indoor heat exchanger (31) is connected to the main liquid line (4L) and the main gas line (4G) via the indoor liquid pipe (3L) and the indoor gas pipe (3G), and Three
L) is provided with an indoor electric expansion valve (32).

-Structure of the piping unit-The air conditioner (10) is provided with a piping unit (12) which is a connection circuit, and the piping unit (12)
Is the branch liquid line (5L) of each outdoor unit (2A, 2B, 2C).
-A, 5L-B, 5L-C) and branch gas lines (5G-A, 5G-B, 5G
-C), main liquid line (4L) and main gas line (4
G) is connected.

Specifically, the branch liquid lines (5L-A, 5L-B, 5L
-C) is a branch liquid pipe (5LAa, 5LBa, 5LCa) extending from each outdoor unit (2A, 2B, 2C) to the outside, and the branch liquid pipe (5LAa, 5LBa, 5LCa).
a, 5LBa, 5LCa) and the branch fluid passage (5LAb, 5LCa)
LBb, 5LCb).

The above branch gas lines (5G-A, 5G-B, 5G-C)
Is a branch gas pipe (5GAa, 5GBa, 5GCa) extending outside the outdoor unit (2A, 2B, 2C), and the branch gas pipe (5GAa,
Branch gas passage (5GAb, 5G) that is continuous with the outer end of 5GBa, 5GCa)
Bb, 5GCb).

The main liquid line (4L) is connected to a main liquid pipe (4L-a) connected to the indoor liquid pipe (3L) of the indoor unit (3A, 3B, 3C). ) And the branch liquid passage (5L) of each outdoor unit (2A, 2B, 2C)
Ab, 5LBb, 5LCb) are constituted by a main liquid passage (4L-b) communicating via a receiver (11).

The main gas line (4G) is connected to a main gas pipe (4G-a) connected to the indoor gas pipe (3G) of the indoor unit (3A, 3B, 3C). ) And a main gas passage (4G-b) which is continuous with one end of the outdoor unit (2A, 2B, 2C) and the branch gas passage (5GAb, 5GBb, 5GCb) of each outdoor unit (2A, 2B, 2C).

The piping unit (12) is connected to the branch liquid lines (5L-A, 5L) on the side of each outdoor unit (2A, 2B, 2C).
-B, 5L-C) branch gas passage (5LAb, 5LBb, 5LCb) and branch gas line (5G-A, 5G-B, 5G-C) branch gas passage (5GA
b, 5GBb, 5GCb), the main liquid passage (4L-b) of the main liquid line (4L) and the main gas passage (4G-b) of the main gas line (4G), and the receiver (11) integrally. It is formed and unitized.

Further, the piping unit (12) has a first
The gas on-off valve (VR-1) and the second gas on-off valve (VR-2) are integrally unitized. The first gas on-off valve (VR-1)
Is the branch gas passage (5GBb) on the second outdoor unit (2B) side
And the second gas on-off valve (VR-2) is provided in the branch gas passage (5GCb) on the third outdoor unit (2C) side. This constitutes an opening / closing mechanism for opening and closing the branch gas passage (5GCb).

The first gas on-off valve (VR-1) and the second gas on-off valve (VR-2) are constituted by external pressure equalizing type reversible valves, and are connected to a pilot circuit (50). The pilot circuit (50) has two check valves (CV, CV), and has a branch gas passage (5GAb) on the first outdoor unit (2A) side and a first outdoor unit (2A) side described later. First oil equalization auxiliary passage (77-
A) and a high-pressure circuit (51) for guiding the high-pressure refrigerant and having two check valves (CV, CV);
A branch gas passage (5GAb) on the outdoor unit (2A) side and a first equalizing auxiliary passage (77) on the first outdoor unit (2A) side, which will be described later.
-A) Low-voltage circuit (52) connected to and maintaining the low-voltage state
And

The pilot circuit (50) is connected to a high-pressure circuit (51) and a low-pressure circuit (52) by a switching valve (50-S).
And the first gas on-off valve (VR-1) and the second gas on-off valve (VR-
2) to control the first gas on-off valve (VR-1) to be fully closed when the second outdoor unit (2B) is stopped during the heating operation, and to control the third outdoor unit during the heating operation. The second gas on-off valve (VR-2) is controlled to be fully closed when the unit (2C) stops.

The second outdoor unit (2B) and the third outdoor unit (2B)
The outdoor electric expansion valves (24, 24) of the outdoor unit (2C) are not provided in the piping unit (12), but correspond to the first gas on-off valve (VR-1) and the second on-off valve, The opening / closing mechanism that opens and closes each branch liquid line (5L-A, 5L-B, 5L-C) is also used. During cooling operation and heating operation, the second outdoor unit (2B) and the third outdoor unit (2C) ) Is configured to be fully closed when stopped.

-Structure of pressure equalizing line- A pressure equalizing line (60) is connected between the outdoor units (2A, 2B, 2C), and the pressure equalizing line (60) is connected to each outdoor unit (2). 2A, 2B, 2C) outdoor heat exchanger (23)
Is connected to the gas-side refrigerant pipes (25, 25, 25), and is configured to allow bidirectional refrigerant flow between the outdoor units (2A, 2B, 2C).

Further, the pressure equalizing line (60) is provided with a pressure equalizing pipe (61-A, 61-A) extending outside each outdoor unit (2A, 2B, 2C).
61-B, 61-C), the pressure equalizing passage (62) is continuously formed at the outer end. The equalizing passage (62) is formed in the piping unit (12), and branches from the first outdoor unit (2A) to the second outdoor unit (2B) and the third outdoor unit (2C). A first equalizing valve (SVB1) and a second equalizing valve (SVB2) are provided in the branch pipe portion.

When the cooling operation of the second outdoor unit (2B) is stopped, the first equalizing valve (SVB1) is fully closed to prevent the refrigerant from flowing to the second outdoor unit (2B). (SVB
The configuration 2) is configured to be fully closed when the cooling operation of the third outdoor unit (2C) is stopped, and to block the flow of the refrigerant to the third outdoor unit (2C).

-Configuration of Auxiliary Refrigerant Circuit- Each of the outdoor units (2A, 2B, 2C) has the structure shown in FIGS.
As shown in FIG. 7, an oil return mechanism (70) for returning lubricating oil to the compression mechanism (21) is provided. The oil return mechanism (70) is composed of an oil separator (71) and a first oil return pipe (72). ) And the second oil return pipe (7
3) and an oil equalization bypass pipe (74).

On the other hand, the suction pipe (25-S) of the downstream compressor (COMP-2), which is a part of the refrigerant pipe (25), is connected to the suction pipe (25-S) of the upstream compressor (COMP-1). S), the pressure loss is set higher than that of the compressor (COMP-1 and COMP-2).
5) is connected. As a result, the downstream compressor (COMP-1) on the low pressure side is higher than the upstream compressor (COMP-1) on the high pressure side.
-2) Lubricating oil is supplied.

The oil separator (71) includes an upstream compressor (COMP-1) and a downstream compressor (CO
MP-2) and the discharge pipe (25-D, 25-D)
The discharge pipes (25-D, 25-D) of each compressor (COMP-1, COMP-2) are provided with check valves (CV-1, CV-2). Furthermore, between the upper part of the upstream compressor (COMP-1) and the downstream of the check valve (CV-1) of the discharge pipe (25-D), and the downstream compressor (COMP-1).
Oil discharge pipes (76, 76) are respectively connected between the upper part of 2) and the downstream side of the check valve (CV-2) of the discharge pipe (25-D).

Each of the oil discharge pipes (76, 76) is configured to discharge, for example, lubricating oil accumulated in an upper portion of the scroll compressor to the discharge pipes (25-D, 25-D). . Also, the check valve (CV-1) of the upstream compressor (COMP-1)
When the refrigerant circulation amount is small, a line resistance is added to ensure that the lubricating oil is discharged from the discharge pipe (25-D).

The first oil return pipe (72) includes a capillary tube (CP) and is connected to the oil separator (71) and the suction pipe (25-S) of the upstream compressor (COMP-1). The lubricating oil accumulated in the oil separator (71) is always returned to the upstream compressor (COMP-1). The second oil return pipe (73) includes an oil return valve (SVP2) and is connected to the oil separator (71) and the suction pipe (25-S) of the downstream compressor (COMP-2). The oil return valve (SVP2) is configured to open every predetermined time and return the lubricating oil accumulated in the oil separator (71) to the suction side of the compression mechanism (21).

The oil equalizing bypass pipe (74) is connected to an oil equalizing valve (SV
O1), one end of which has an oil return valve (SV) of a second oil return pipe (73).
The other end is connected to the equalizing pipes (61-A, 61-B, 61-C) of the equalizing line (60) on the upstream side of P2). Then, in order to execute the oil equalizing operation together with the oil equalizing bypass pipe (74), the equalizing passage (62) of the equalizing line (60) includes:
First equalizing auxiliary passage (77-A) and second equalizing auxiliary passage (77-B)
And the third equalizing auxiliary passage (77-C) are connected, and each of the equalizing auxiliary passages (77-A, 77-B, 77-C) is incorporated in the piping unit (12).

One end of the first equalizing auxiliary passage (77-A) is on the first outdoor unit (2A) side of the equalizing passage (62), and the other ends are the second outdoor unit (2B) and the third outdoor. Connected to the junction of the branch gas passages (5GBb, 5GCb) of the unit (2C),
Equipped with an oil equalizing auxiliary valve (SVY1) and a check valve (CV).

The second equalizing auxiliary passage (77-B) has one end on the side of the second outdoor unit (2B) of the equalizing passage (62) and the other end on the branch gas passage of the first outdoor unit (2A). (5GAb), and includes a second oil equalization auxiliary valve (SVY2) and a check valve (CV).

The third equalizing auxiliary passage (77-C) has one end on the third outdoor unit (2C) side of the equalizing passage (62) and the other end on the branch gas passage of the first outdoor unit (2A). (5GAb), and includes a third oil equalization auxiliary valve (SVY3) and a check valve (CV).

Then, the oil equalizing valve (SVO1, SVO1, SVO1)
And the first to third oil equalizing auxiliary valves (SVY1, SVY2, SVY3)
When performing oil leveling operation once every 2-3 hours (2-3 minutes)
Alternatively, it is configured to open and close when the oil equalizing operation is performed, such as after the oil return operation is completed or after the defrost operation during the heating operation.

The branch gas passage (5GB) of the second outdoor unit (2B) and the second equalizing auxiliary passage (77-B), and the branch gas passage (5GCb) of the third outdoor unit (2C). ) And the third equalizing auxiliary passage (77-C) have a capillary tube (CP), and the first gas on-off valve (VR-1) during the heating operation.
Auxiliary refrigerant passages (12-s, 12-s) for discharging refrigerant leaking from the second gas on-off valve (VR-2) are connected.

Each of the outdoor units (2A, 2B, 2C)
A liquid injection pipe (2j) is connected to the branch liquid pipes (5LAa, 5LBa, 5LCa), and the liquid injection pipe (2j) is branched into two, and the injection valves (SVT1, SVT2) and the capillary are connected. Tube (CP,
CP) to the upstream compressor (COMP-1) and the downstream compressor (COMP-2). The above liquid injection valves (SVT1, SVT2) are connected to each compressor (COMP-1, COMP
It is configured to open when the temperature of the discharged gas refrigerant excessively rises in -2) to lower the temperature of the discharged gas refrigerant.

A hot gas bypass pipe (2h) is connected between the discharge side and the suction side of the compression mechanism (21) in each of the outdoor units (2A, 2B, 2C). Has a hot gas valve (SVP1) and is connected to the upstream side of the four-way switching valve (22) and the upstream side of the accumulator (26). The hot gas valve (SVP1) is configured to equalize the pressure on the discharge side and the pressure on the suction side of the compression mechanism (21) mainly at the time of starting or the like.

An auxiliary bypass pipe (2b) is connected to the second outdoor unit (2B) and the third outdoor unit (2C) between the suction side and the discharge side of the compression mechanism (21). The bypass pipe (2b) includes a check valve (CV) that allows the refrigerant to flow only from the suction side to the discharge side of the compression mechanism (21), and the upstream side of the four-way switching valve (22) and the accumulator (26). Connected to the upstream side. When the second outdoor unit (2B) and the third outdoor unit (2C) stop during the heating operation, the auxiliary bypass pipe (2b) is connected to the branch gas line (5G-B,
5G-C) is configured to be drawn into the first outdoor unit (2A), bypassing the compression mechanism (21).

The low pressure circuit (52) of the receiver (11) and the pilot circuit (50) in the piping unit (12).
Is connected to a gas vent passage (12-g). The gas vent passage (12-g) is provided with a gas vent valve (SVTG) and is incorporated in the piping unit (12), and the gas vent valve (SVTG)
Are configured to open for high-pressure protection during cooling operation and low-pressure protection during heating operation.

On the other hand, each outdoor unit (2A, 2B, 2C)
The shut-off valves (OV, OV, ...) for the branch liquid pipes (5LAa, 5LBa, 5LCa), branch gas pipes (5GAa, 5GBa, 5GCa) and pressure equalizing pipes (61-A, 61-B, 61-C) Are provided, and the closing valves (OV, OV,...) Are opened at the time of installation or the like, and thereafter are always opened.

-Configuration of Sensors- Various sensors are provided in the outdoor units (2A, 2B, 2C) and the indoor units (3A, 3B, 3C).
Each outdoor unit (2A, 2B, 2C) has an outdoor air temperature T1
The outdoor air temperature sensor (Th-1) that detects the temperature of the outdoor heat exchanger (23)
An outdoor liquid temperature sensor (Th-2) that detects the liquid refrigerant temperature T2 of the outdoor heat exchanger (23) is located near the branch liquid lines (5L-A, 5L-
B, 5L-C), the refrigerant temperature T discharged from the compression mechanism (21)
The discharge temperature sensors (Th31, Th32) that detect the pressure 3 detect the refrigerant temperature T4 of the compression mechanism (21) to the discharge pipes (25-D, 25-D) of the compressors (COMP-1, COMP-2). The detected suction temperature sensor (Th-4) is connected to the suction side refrigerant pipe (25) of the compression mechanism (21).
Oil temperature sensors (Th51, Th52) that detect the oil temperature To of the lubricating oil inside each compressor (COMP-1, COMP-2)
An outdoor gas temperature sensor (Th-6) for detecting the gas refrigerant temperature T6 of the outdoor heat exchanger (23) is provided in the gas-side refrigerant pipe (25) below the first and second components (COMP-2).

Further, the first outdoor unit (2A) includes:
The high pressure sensor (SP-H) that detects the refrigerant pressure PH discharged from the compression mechanism (21) is connected to the refrigerant pipe (25) on the discharge side of the compression mechanism (21).
In addition, a low-pressure pressure sensor (SP-L) for detecting the suction refrigerant pressure PL of the compression mechanism (21) is provided in the suction-side refrigerant pipe (25) of the compression mechanism (21), respectively. The high-pressure protection switches (H-PS, H-PS) that operate when the discharge refrigerant pressure of the COMP-1 and COMP-2) reaches a predetermined high pressure are applied to each compressor (CO
MP-1 and COMP-2) are provided in the discharge pipe (25-D, 25-D).

The second outdoor unit (2B) and the third room
Since the external unit ( 2C ) is provided with the pressure equalizing line (60), the high pressure sensor (SP-H) and the low pressure sensor (SP-L) are provided like the first outdoor unit (2A). High pressure protection switches (H-PS, H-PS) that operate when the refrigerant pressure discharged from each compressor (COMP-1, COMP-2) reaches a predetermined high pressure
Is the discharge pipe (25-D, 25-D) of each compressor (COMP-1, COMP-2)
In addition, the high pressure control switch (HPSC), which operates when the refrigerant pressure discharged from the compression mechanism (21) reaches a predetermined high pressure lower than the high pressure protection switch (H-PS, H-PS), discharges the compression mechanism (21). A low-pressure protection switch (L-PS) that operates when the suction refrigerant pressure of the compression mechanism (21) becomes a predetermined low pressure is provided on the suction-side refrigerant pipe (25) of the compression mechanism (21), respectively, on the side refrigerant pipe (25). Has been.

On the other hand, each of the indoor units (3A, 3B, 3C) has a room temperature sensor (Th-7) for detecting the indoor air temperature T7 near the indoor fan (31-F). The indoor liquid temperature sensor (Th-8) that detects the liquid refrigerant temperature T8 of the indoor heat exchanger (31) is connected to the indoor liquid pipe (3L). ) Is indoor gas piping (3G)
Respectively.

-Control Configuration- The air conditioner (10) includes a controller (80), and the controller (80) includes sensors (Th11 to SP).
-L) and switch (H-PS to L-PS) detection signals are input,
The opening degree of each electric expansion valve (24-32), the capacity of the compression mechanism (21), etc. are controlled based on the detection signal of each sensor (Th11-SP-L).

As a feature of the present invention, the controller (80) is provided with a refrigerant recovery unit (81), an air volume changing unit (82), and a low air volume unit (83). The refrigerant recovery means (81) is configured to operate the branch liquid line (5L-A) in the first outdoor unit (2A) when one of the outdoor units (2A) is abnormal, for example, when the first outdoor unit (2A) is abnormal. The other second outdoor unit (2B) and the third outdoor unit (2C) are operated with the closing valve (OV) closed to collect the refrigerant of the abnormal first outdoor unit (2A). ing. After the refrigerant is recovered, the closing valves (OV, OV) of the branch gas line (5G-A) and the pressure equalizing pipe (61-A) are closed, and then the abnormal low pressure refrigerant pressure of the first outdoor unit (2B) is closed. Becomes a predetermined value, the refrigerant recovery is terminated.

The air volume changing means (82) functions when the first outdoor unit (2A) is abnormal, and when the refrigerant recovery means (81) recovers the refrigerant, the normal outdoor unit (2B), for example, the second outdoor unit (2B)
When the suction refrigerant temperature T4 of the compression mechanism (21) in the outdoor unit (2B) is equal to or higher than a predetermined temperature with respect to the outdoor air temperature T1, which is the outdoor air temperature (T4> T1-5 ° C), the indoor heat exchanger (31)
While the air volume of the outdoor fan (31-F) is sequentially reduced, if the suction refrigerant temperature T4 of the compression mechanism (21) is lower than a predetermined temperature with respect to the outdoor air temperature T1 (T4 <T1-20 ° C.), the indoor The air volume of the indoor fan (31-F) of the heat exchanger (31) is sequentially increased.

The low air volume means (83) functions when the second outdoor unit (2B) or the third outdoor unit (2C) is abnormal, and when the refrigerant recovery means (81) recovers the refrigerant, the indoor heat exchanger (31) operates. ), The air volume of the indoor fan (31-F) is set to a constant low air volume.

When the refrigerant recovery means (81) recovers the refrigerant, all the indoor units (3A, 3B, 3C) are forcibly executed in the cooling operation, and the indoor electric expansion valve (32) is controlled in the degree of superheat. It is configured to:

<Operation of Air-Conditioning Operation> Next, a control operation of the air-conditioning operation in the air conditioner (10) will be described.

First, during the cooling operation, the four-way switching valve (22) switches to the solid line in FIGS. 3 and 4, and the high pressure discharged from the compression mechanism (21) of each outdoor unit (2A, 2B, 2C). The gas refrigerant condenses in the outdoor heat exchanger (23) to become a liquid refrigerant,
This liquid refrigerant is supplied to the main liquid passage (4L) of the piping unit (12).
Merge at -b). Thereafter, the liquid refrigerant is decompressed by the indoor electric expansion valve (32) and then evaporates in the indoor heat exchanger (31) to become a low-pressure gas refrigerant. The flow is divided into the passages (5GAb, 5GBb, 5GCb), returned to the compression mechanisms (21) of the outdoor units (2A, 2B, 2C), and the circulation operation is repeated.

On the other hand, during the heating operation, the four-way switching valve (22) changes to the broken line in FIGS. 3 and 4, and is discharged from the compression mechanism (21) of each outdoor unit (2A, 2B, 2C). The high-pressure gas refrigerant flows into the piping unit (12), merges in the main gas passage (4G-b) of the piping unit (12), and then flows into the indoor units (3A, 3B, 3C). The gas refrigerant is condensed in the indoor heat exchanger (31) to become a liquid refrigerant, and the liquid refrigerant is condensed in the main liquid passage (4L-
The liquid is diverted from b) to the branch liquid passage (5LAb, 5LBb, 5LCb) on each outdoor unit (2A, 2B, 2C) side. After that, the liquid refrigerant is decompressed by the outdoor electric expansion valve (24) and then evaporated by the outdoor heat exchanger (23) to become a low-pressure gas refrigerant, and the compression mechanism (2A, 2B, 2C) of each outdoor unit (2A, 2B, 2C) Returning to 21), this circulation operation is repeated.

During the cooling operation and the heating operation,
The controller (80) is an indoor electric expansion valve (32, 32, 32)
In addition to controlling the degree of opening of each outdoor electric expansion valve (24, 24, 24), each outdoor unit (2A, 2B,
2C) controls the capacity of the compression mechanism (21). Specifically, the controller (80) controls the first outdoor unit (2
The upstream compressor (COMP-1) of A) is controlled almost linearly in response to the load by inverter control,
Start and stop control of the downstream compressor (COMP-2) of the outdoor unit (2A) and each compressor (COMP-1, COMP-2) of the second outdoor unit (2B) and the third outdoor unit (2C) are doing.

Then, the indoor unit (3A, 3B, 3C)
When the load on the third outdoor unit (2C) and the second
Operation is stopped in the order of the outdoor unit (2B), and conversely, when the load of the indoor unit (3A, 3B, 3C) increases, operation starts in the order of the second outdoor unit (2B) and the third outdoor unit (2C) Will be.

In both the cooling operation and the heating operation, when the outdoor units (2A, 2B, 2C) are operating, the first equalizing valve (SVB1) and the second equalizing valve (SVB1) are operated.
2) is open, and in the cooling operation, the high-pressure gas refrigerant flows almost evenly in each outdoor heat exchanger (23, 23, 23), and in the heating operation, the low-pressure gas refrigerant flows in each outdoor heat exchanger (23, 23). 23, 23).

That is, during the cooling operation, for example, when the operating capacity of the third outdoor unit (2C) becomes large with respect to the cooling load, a part of the refrigerant discharged from the compression mechanism (21) becomes equal to the pressure equalizing line (60). Through the outdoor heat exchangers (23, 2) in the first outdoor unit (2A) and the second outdoor unit (2B).
3) will flow. Conversely, during heating operation,
For example, when the operating capacity of the third outdoor unit (2C) increases with respect to the heating load, a part of the refrigerant sucked into the compression mechanism (21) of the first outdoor unit (2A) and the second outdoor unit (2B). Is sucked into the compression mechanism (21) of the third outdoor unit (2C) through the pressure equalizing line (60).

-Opening / closing operation of various valves-When the cooling operation of the third outdoor unit (2C) is stopped,
The outdoor electric expansion valve (24) and the second equalizing valve (SVB2) are closed to prevent the liquid refrigerant from accumulating in the stopped third outdoor unit (2C). Similarly, the second outdoor unit (2B) When the cooling operation is stopped, the outdoor electric expansion valve (24) and the first equalizing valve (SVB1) are closed, and the stopped second outdoor unit (2) is stopped.
In addition to preventing the liquid refrigerant from accumulating in B), the shortage of the refrigerant amount between the first outdoor unit (2A) and the indoor units (3A, 3B, 3C) is prevented. When the cooling operation of the third outdoor unit (2C) and the second outdoor unit (2B) is stopped, since the branch gas lines (5G-A, 5G-B, 5G-C) are in a low pressure state, the first gas The on-off valve (VR-1) and the second gas on-off valve (VR-2) are open.

On the other hand, when the heating operation of the third outdoor unit (2C) is stopped, the outdoor electric expansion valve (24) and the second gas on-off valve (VR-2) are closed, and the stopped third outdoor unit (2C) is stopped. )
When the heating operation of the second outdoor unit (2B) is stopped, the outdoor electric expansion valve (24) and the first gas on-off valve (VR-1) are closed and stopped. Prevents liquid refrigerant from accumulating in the second outdoor unit (2B) and prevents shortage of refrigerant between the first outdoor unit (2A) etc. and each indoor unit (3A, 3B, 3C) I do.
The third outdoor unit (2C) and the second outdoor unit (2C)
When the heating operation is stopped in B), the equalizing line (60) communicates with the low pressure side of the first outdoor unit (2A) or the like, so that the second equalizing valve (SVB2) and the first equalizing valve (SVB1) are opened. I have.

Further, immediately after the heating operation of the third outdoor unit (2C) and the second outdoor unit (2B) is stopped, for example, when the third outdoor unit (2C) is stopped, the third outdoor unit (2C) The outdoor electric expansion valve (24) and the second gas on-off valve (VR-2) are opened for a predetermined time.
Leave open for 2 minutes. As a result, the high-pressure gas refrigerant from the first outdoor unit (2A) and the like passes through the branch gas line (5G-C) and the auxiliary bypass pipe (2b) of the third outdoor unit (2C) and the branch liquid line (5L-C). ), And transfers the liquid refrigerant in the stopped third outdoor unit (2C) to the main liquid line (4).
L) to prevent refrigerant shortage.

During the cooling operation and the heating operation, each oil equalizing valve (SVO1, SVO1, SVO1) and each oil equalizing auxiliary valve (SV
Y1, SVY2 and SVY3 are closed together while the oil separator (7
The lubricating oil accumulated in 1) always returns from the first oil return pipe (72) to the compression mechanism (21), and the oil return valve (SVP)
2) is opened, and the lubricating oil collected in the oil separator (71) is returned from the second oil return pipe (73) to the compression mechanism (21).

Further, in both the cooling operation and the heating operation, the oil equalizing valves (SVO1, SVO1, SVO1) and the oil equalizing auxiliary valves (SVY1, SVY2, SVY3) are appropriately opened and closed to control the oil leveling. The operation is performed so that the amount of lubricating oil in the compression mechanism (21) of each outdoor unit (2A, 2B, 2C) is equalized.

-Refrigerant Recovery Method-As a feature of the present invention, when one outdoor unit (2A) is abnormal, refrigerant recovery is performed.
A case where an abnormality occurs in the outdoor unit (2A) will be described.

In this case, first, the first outdoor unit (2A)
Close the closing valve (OV) in the branch fluid line (5LAa).
Then, the refrigerant recovery means (81) is connected to the second outdoor unit (2
B) and the third outdoor unit (2C) are operated in the cooling operation cycle, and the refrigerant of the first outdoor unit (2A) is recovered to the second outdoor unit (2B) and the third outdoor unit (2C) side. At that time, only the upstream compressor (COMP-1) is driven,
The outdoor electric expansion valve (24) is set to a fully open state. Also,
All the indoor units (3A, 3B, 3C) are forcibly executed in the cooling operation, the indoor electric expansion valve (32) is controlled in the degree of superheat, and the air volume changing means (82) is controlled by the indoor fan ( 31-F).

[0080] The following, closing the branch gas pipe of the first outdoor unit (2A) and (5GAa) equalizing pipe (61-A) and the shut-off valve (OV, OV). Next, in the first outdoor unit ( 2A )
When the pressure detected by the pressure sensor (not shown ) on the suction side of the compression mechanism ( 21 ) drops below the outdoor air temperature equivalent pressure, the refrigerant recovery is terminated. Then, maintenance of the first outdoor unit (2A) is performed.

The control of the indoor fan (31-F) by the air volume changing means (82) will be described with reference to FIG. First, in the initial state in which the refrigerant recovery is started, in the state T1, the high speed which is the H tap of the indoor fan (31-F) is set, and in this state T1, the compression mechanism (21B) in the second outdoor unit (2B) is set. ) When the intake refrigerant temperature T4 is equal to or higher than the predetermined temperature with respect to the outdoor air temperature T1 (T4> T1-5)
C.) for 3 minutes (condition A is satisfied), the process proceeds to the state T2, and the low speed is set as the L tap of the indoor fan (31-F). Furthermore, in this state T2, the state in which the suction refrigerant temperature T4 of the compression mechanism (21) in the second outdoor unit (2B) is higher than the outdoor air temperature T1 by a predetermined temperature (T4> T1-5)
C.) for 3 minutes (condition A is satisfied), the process moves to state T3, and the speed is set to the low speed, which is the LL tap of the indoor fan (31-F). Furthermore, in this state T3, the state in which the suction refrigerant temperature T4 of the compression mechanism (21) in the second outdoor unit (2B) is higher than the outdoor air temperature T1 by a predetermined temperature (T4> T1−
When (5 ° C.) continues for 3 minutes (condition A is satisfied), the process shifts to state T4 and stops the indoor fan (31-F). In other words, when both the outdoor and the indoor are at a high temperature, the low-pressure refrigerant pressure PL does not decrease, so that the wind speed of the indoor fan (31-F) decreases, and the decrease in the wind speed causes the opening of the indoor electric expansion valve (32) to overheat. It becomes smaller by the degree control, and lowers the refrigerant circulation amount.

Conversely, in the state T4, the suction refrigerant temperature T4 of the compression mechanism (21) in the second outdoor unit (2B)
Is below a predetermined temperature with respect to the outdoor air temperature T1 (T4 <T1
(−20 ° C.) for 5 minutes (condition B is satisfied), the state T
Move to 3, and set to the slow speed which is the LL tap of the indoor fan (31-F). Further, in this state T3, the suction refrigerant temperature T4 of the compression mechanism (21) in the second outdoor unit (2B)
Is below a predetermined temperature with respect to the outdoor air temperature T1 (T4 <T1
(−20 ° C.) for 5 minutes (condition B is satisfied), the state T
Move to 2, and set to low speed, which is the L tap of the indoor fan (31-F). Furthermore, in this state T2, the suction refrigerant temperature of the compression mechanism (21) in the second outdoor unit (2B)
A state where T4 is equal to or lower than a predetermined temperature with respect to the outdoor air temperature T1 (T4 <
If (T1-20 ° C.) continues for 5 minutes (condition B is satisfied), the state shifts to state T1, and the high speed is set as the H tap of the indoor fan (31-F). Then, the above operation is repeated.

On the other hand, when the second outdoor unit (2B) is abnormal, the branch liquid pipe (5L) of the second outdoor unit (2B)
Close the closing valve (OV) in Ba). Then, the refrigerant recovery means (81) causes the first outdoor unit (2A) and the third outdoor unit (2C) to operate in the cooling operation cycle, and transfers the refrigerant of the second outdoor unit (2B) to the first outdoor unit (2A). And to the third outdoor unit (2C) side. At that time, only the upstream compressor (COMP-1) is driven, and the upstream compressor (COMP-1) of the first outdoor unit (2A) is PI-controlled so that the low-pressure refrigerant pressure PL is constant, and The outdoor electric expansion valve (24) is set in a fully open state. In addition, all the indoor units (3A, 3B, 3C) are forcibly performed the cooling operation, the indoor electric expansion valve (32) is controlled in the degree of superheat, and the low air volume means (83) is controlled by the indoor fan (31-C). Set F) to low speed, which is L taps.

Thereafter, when the detected pressure of a pressure sensor (not shown) attached to the suction side of the compression mechanism (21) in the second outdoor unit (2B) becomes lower than the pressure corresponding to the outdoor air temperature, the refrigerant collection is terminated. Shut-off valve (OV, OV) between branch gas pipe (5GBa) and equalizing pipe (61-B) of 2 outdoor unit (2B)
To close. Then, maintenance of the second outdoor unit (2B) is performed. Then, the same operation is performed in the case of the third outdoor unit (2C). in this case,
Since the capacity of the first outdoor unit (2A) is variable,
The indoor fan (31-F) is set only at a low speed of L tap.

As described above, according to the present embodiment, since the refrigerant is recovered when one of the outdoor units (2A) is abnormal, the refrigerant can be discharged to the atmosphere. Since there is no refrigerant, it is possible to effectively use the refrigerant.

When the refrigerant is collected, the indoor fan (31-F)
Since the air volume is reduced, the low-pressure refrigerant pressure can be surely reduced, so that the refrigerant can be quickly recovered.

In particular, since the refrigerant recovery means (81) controls the degree of superheat of the indoor electric expansion valve (32) of the indoor unit (3A, 3B, 3C), the air flow of the indoor fan (31-F) decreases. Since the opening degree of the indoor electric expansion valve (32) is controlled to be small, the low-pressure refrigerant pressure can be reliably reduced by the air volume control, and the refrigerant can be recovered more quickly.

-Other Modifications- In the above embodiment, the air volume changing means (82) controls the indoor fan (31-F) based on the suction refrigerant temperature T4 of the compression mechanism (21). The air volume changing means (82) is a saturation temperature corresponding to an evaporation pressure (hereinafter simply referred to as an evaporation temperature Te) calculated based on the suction refrigerant pressure PL of the compression mechanism (21) detected by the low pressure pressure sensor (SP-L). ) The indoor fan (31-F) may be controlled based on the evaporation temperature Te.

The low-pressure pressure sensor (SP-L) is
Although it is provided only in the outdoor unit (2A), when the refrigerant recovery is required, the low pressure sensor (SP-L) functions normally even when the actuator such as the compression mechanism (21) is abnormal. Since the normal evaporation temperature Te of the second outdoor unit (2B) and the normal third outdoor unit (2C) can be derived, the detection signal of the low pressure sensor (SP-L) is used. .

That is, when the state where the evaporation temperature Te is equal to or higher than the predetermined temperature with respect to the outdoor air temperature T1 (Te> T1−10 ° C.) continues for three minutes, the indoor fan (31-F) is switched from the high speed of the H tap to the low level. Set the tap to low speed. Furthermore, in this state, when the state where the evaporation temperature Te is equal to or higher than the predetermined temperature with respect to the outdoor air temperature T1 (Te> T1−10 ° C.) continues for 3 minutes, the speed becomes the LL tap of the indoor fan (31-F). Set. Furthermore, when the state where the evaporation temperature Te is equal to or higher than the predetermined temperature with respect to the outdoor air temperature T1 (Te> T1-10 ° C.) continues for three minutes, the indoor fan (31-F) is stopped.

On the contrary, the evaporation temperature Te is equal to the outdoor air temperature.
5 when the temperature is less than the predetermined temperature for T1 (Te <T1-20 ℃)
Minutes, the indoor fan (31-F) is switched from the stopped state to LL
Set to a very slow tap. Further, the state where the evaporation temperature Te is equal to or lower than the predetermined temperature with respect to the outdoor air temperature T1 (Te <T1−20)
° C) for 5 minutes, set to low speed which is L tap of indoor fan (31-F). Furthermore, a state in which the evaporation temperature Te is equal to or lower than a predetermined temperature with respect to the outdoor air temperature T1 (Te <T1−20)
C.) for 5 minutes, the high speed, which is the H tap of the indoor fan (31-F), is set. At this time, the degree of opening of the indoor electric expansion valve (32) is controlled by the degree of superheat. Other configurations, functions and effects are the same as those of the previous embodiment.

In this embodiment, the air conditioner (10) capable of performing the cooling operation and the heating operation has been described. However, the present invention is also applicable to an air conditioner dedicated to the cooling operation or the heating operation. Of course you can.

In the present invention, it is not always necessary to provide the pressure equalizing line (60).

According to the second aspect of the present invention, it is not always necessary to control the degree of superheat of the opening of the indoor electric expansion valve (32), but only the air volume control of the indoor fan (31-F). Due to the decrease in the wind speed, the gas refrigerant runs short and the low-pressure refrigerant pressure PL decreases.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a refrigerant circuit diagram of the air conditioner.

FIG. 3 is a refrigerant circuit diagram of a first outdoor unit.

FIG. 4 is a refrigerant circuit diagram of second and third outdoor units.

FIG. 5 is a state transition diagram of an indoor fan at the time of refrigerant recovery.

[Explanation of symbols]

10 Air conditioner 2A, 2B, 2C outdoor unit 21 Compression mechanism COMP-1, COMP-2 compressor 22 Four-way switching valve 23 Outdoor heat exchanger 24 Outdoor electric expansion valve 3A, 3B, 3C indoor unit 31 Indoor heat exchanger 32 Indoor electric expansion valve 4L main liquid line 4G main gas line 5L-A, 5L-B, 5L-C Branch liquid line 5G-A, 5G-B, 5G-C branch gas line 80 Controller 81 Refrigerant recovery means 82 Air volume change means 83 Low air volume means

Continuation of the front page (56) References JP-A-6-300379 (JP, A) JP-A-63-75445 (JP, A) JP-A-5-164437 (JP, A) JP-A-3-50438 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F25B 43/00-49/04

Claims (4)

(57) [Claims] A compression mechanism (21) and one end of a compression mechanism (2
1) and the other end is connected to a branch liquid line (5L-A, 5L-B,
) Are connected to the heat source side heat exchanger (23), and the plurality of heat source units (2A) connected to the compression mechanism (21) are connected to the branch gas lines (5G-A, 5G-B, ...). , 2B, ...) and each of the heat source units (2A, 2B, ...) are connected to a branch liquid line (5L-
A, 5L-B, ...) and branch gas lines (5G-A, 5G-B, ...)
A main liquid line (4L) and a main gas line (4G) connected in parallel via a liquid crystal unit, an expansion mechanism (32) and a use side heat exchanger (31). Multiple usage units (3A, 3B, 3G, 3G) connected in parallel to the main gas line (4G)
…) And the branch liquid line (5L) of each heat source unit (2A, 2B,…)
-A, 5L-B, ...) and branch gas lines (5G-A, 5G-B, ...)
Valves (OV, OV,…) that are always open
When the heat source unit (2A) of the above 1 is abnormal, the shutoff valve (OV) of the branch liquid line (5L-A) in the abnormal heat source unit (2A) is closed, and then the refrigerant is recovered. Means (81) cool other heat source units (2B,…)
Operate in the cell operation cycle to recover the refrigerant of the abnormal heat source unit (2A), then close the shutoff valve (OV) of the branch gas line (5G-A), and Pressure is outdoor air
A refrigerant recovery method for a refrigeration system, wherein the refrigerant recovery is terminated when the temperature falls below a gas temperature equivalent pressure . 2. The refrigerant recovery method for a refrigeration system according to claim 1, wherein when the refrigerant recovery means (81) recovers the refrigerant, it corresponds to the suction refrigerant temperature or the evaporation pressure of the compression mechanism (21) in the normal heat source unit (2B). If the saturation temperature is equal to or higher than the predetermined temperature with respect to the outside air temperature, the use side fan (31-F) of the use side heat exchanger (31)
While the air volume of the compressor (21) is sequentially reduced, if the suction refrigerant temperature or the saturation temperature corresponding to the evaporating pressure of the compression mechanism (21) is equal to or lower than a predetermined temperature with respect to the outside air temperature, the use side fan (31) of the use side heat exchanger (31) -F) Air volume change means (8
(2) A method for recovering refrigerant of a refrigeration system, comprising: 3. The refrigerant recovery method for a refrigeration system according to claim 2, wherein the refrigerant recovery means (81) is configured to use the utilization unit (3) when recovering the refrigerant.
A, 3B,...), Wherein the expansion mechanism (32) is configured to control the degree of superheat. 4. The method for recovering refrigerant of a refrigeration system according to claim 1, wherein a flow rate of a use-side fan (31-F) of the use-side heat exchanger (31) is kept constant when the refrigerant is recovered by the refrigerant recovery means (81). A method for recovering refrigerant in a refrigeration system, comprising a low air volume means (83) for setting a low air volume.