JP2003314909A - Refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To divert existing connection piping for reducing installation costs or the like, and to reliably show refrigerating capability in a refrigerating machine connected to a utilization side by the connection piping. <P>SOLUTION: An outdoor unit (11) that is the refrigerating machine is connected to cold storage units (12, 13) and a refrigeration unit (14) by the connection piping (16, 17). A heat exchanger (36) for supercooling is provided in an outdoor circuit (30). A refrigerant condensed by an outdoor heat exchanger (34) is divided into two, one flows into a first channel (37) of the heat exchanger (36) for supercooling after decompression, and the other flows into a second channel (38) of the heat exchanger (36) for supercooling as it is. The refrigerant cooled by the heat exchanger (36) for supercooling is supplied to the cold storage units (12, 13). Additionally, in the outdoor circuit (30), the first and second compressors (31, 32) for cooling suck the refrigerant evaporated by the cold storage units (12, 13) or the like, and a compressor (33) for supercooling sucks the refrigerant evaporated by the heat exchanger (36) for supercooling. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus which is connected to a user side unit for cooling an object and performs a refrigerating cycle.

[0002]

2. Description of the Related Art Heretofore, refrigerating apparatuses for performing the compression refrigeration cycle have been known and widely used. Generally, this type of refrigerating device is mostly installed outdoors. The refrigerating apparatus is connected to a usage side unit such as a showcase for refrigeration or an indoor unit for air conditioning by connecting pipes on the liquid side and the gas side.

A refrigeration cycle performed by the above refrigeration system will be described. The compressor of the refrigeration system draws in and compresses the refrigerant evaporated in the usage side unit. The refrigerant compressed by the compressor is condensed by the heat exchanger serving as a condenser, and then sent to the utilization side heat exchanger through the liquid side communication pipe. In the usage-side unit, the supplied refrigerant is introduced into a heat exchanger that serves as an evaporator after depressurization, and absorbs heat from the object to be cooled and evaporates. The refrigerant evaporated in the utilization side unit is sent back to the refrigeration system through the gas side communication pipe, and is again sucked into the compressor.

[0004]

As described above, the refrigerant flows back and forth between the outdoor refrigeration system and the indoor use side unit through the connecting pipe. On the other hand, depending on the installation condition of the refrigeration system, the communication pipe may be extremely long and may reach close to 100 m. In such a case, normally, a connecting pipe having a thickness corresponding to the refrigerant circulation amount and the pipe length is used so that the pressure loss of the refrigerant during flowing through the connecting pipe does not become excessive and the refrigerating capacity is deteriorated. .

Here, if the use side unit is additionally installed, the refrigerating apparatus used up to that point may lack the refrigerating capacity, and in such a case, the refrigerating apparatus needs to be replaced. For example, if the conventional refrigeration system had two compressors, it may be replaced with a refrigeration system having three compressors in order to increase the amount of refrigerant circulation and ensure the required refrigeration capacity. . Then, if the connecting pipe is replaced with a thick one in response to the increase in the number of compressors in the refrigeration system, the refrigerant circulation amount will be approximately 1.5 times, and a larger refrigeration capacity will be obtained as the refrigerant circulation amount increases. .

However, if not only the refrigerating apparatus but also the connecting pipe is replaced, there are problems that the cost required for replacing the refrigerating apparatus increases and the construction period is extended. However, simply connecting a refrigeration system with a large number of compressors to the usage-side unit using the existing communication piping would mean using a communication piping with a thickness corresponding to the refrigerant circulation amount obtained in the refrigeration system before replacement. , A larger amount of refrigerant must be circulated than before the refrigeration system was replaced.

Therefore, the pressure loss of the refrigerant while flowing through the connecting pipe may increase, the amount of circulating refrigerant may not increase as expected, or the refrigerant may flash in the connecting pipe on the liquid side. Then, for example, even if the refrigerating apparatus is replaced with one having two compressors instead of three, there is a problem that the essential refrigerating capacity can hardly be increased.

The present invention has been made in view of the above points, and an object of the present invention is to install an existing communication pipe so that it can be used in a refrigeration system connected to a user-side unit through a communication pipe. It is to ensure that the refrigerating capacity is exhibited while reducing costs and shortening the construction period.

[0009]

According to a first aspect of the present invention, there is provided a use side heat exchanger (84, 94, 104) serving as an evaporator and a use side expansion mechanism (82, 92, 102) for depressurizing the supplied refrigerant. Connecting piping (16,1) to the user side unit (12,13,14)
7) connected to the above-mentioned usage side unit (12,13,1
The target is a refrigeration system that performs a refrigeration cycle by circulating a refrigerant between and. Then, the heat source side heat exchanger (34) serving as a condenser, and the supercooling expansion mechanism (40) for depressurizing the first refrigerant which is a part of the refrigerant discharged from the heat source side heat exchanger (34). Then, the second refrigerant, which is the remaining refrigerant after the first refrigerant has been split and is supplied to the utilization side unit (12, 13, 14), is decompressed by the supercooling expansion mechanism (40). First
A supercooling heat exchanger (36) for exchanging heat with the refrigerant to cool it; a first compressor (33) capable of sucking the refrigerant evaporated in the supercooling heat exchanger (36); The second compressor (31, 32) capable of sucking the refrigerant evaporated in the side heat exchangers (84, 94, 104) is provided.

According to a second aspect of the present invention, in the refrigerating apparatus according to the first aspect, the subcooling heat exchanger (36) has the first compressor (3
3) Communication with the suction side and the supercooling heat exchanger (3
6) is provided with a switching mechanism (25) for switching between the state of communicating with the suction side of the second compressor (31, 32).

According to a third aspect of the present invention, in the refrigerating apparatus according to the first aspect, the first compressor (33) is a supercooling heat exchanger (3).
The second compressor (31, 32) sucking only the refrigerant evaporated in 6)
When the user side heat exchanger (84, 94, 104) sucks only the evaporated refrigerant, and when the first compressor (33) fails, the second compressor (31, 32) causes the user side heat exchanger ( 84, 94, 104) and the refrigerant evaporated in the supercooling heat exchanger (36) can be sucked in.

According to a fourth aspect of the present invention, in the refrigeration system of the first aspect, the suction side of the first compressor (33) communicates with the subcooling heat exchanger (36) and the first compressor (33). ) Is provided with a switching mechanism (26) for switching between a state in which the suction side communicates with the use side heat exchanger (84, 94, 104).

According to a fifth aspect of the present invention, in the refrigeration system of the first aspect, the first compressor (33) is a subcooling heat exchanger (3).
The second compressor (31, 32) sucking only the refrigerant evaporated in 6)
When the user side heat exchanger (84, 94, 104) sucks only the evaporated refrigerant, and when the second compressor (31, 32) fails, the first compressor (33) causes the user side heat exchanger ( 84, 94, 104) and the operation of sucking the evaporated refrigerant is possible.

-Operation- In the invention of claim 1, the refrigeration system (11) has the connecting pipe (16,1).
It is connected to the user side unit (12,13,14) via 7). The number of the use side units (12, 13, 14) connected to the refrigeration system (11) does not need to be one, and for example, a plurality of use side units (12, 13, 14) are provided for the refrigeration system (11). ) May be connected.

The refrigerant condensed in the refrigerating apparatus (11) of the present invention passes through the connecting pipe (16) and the use side unit (12, 13, 1).
4) sent to. The refrigerant introduced into the use side unit (12, 13, 14) is decompressed by the use side expansion mechanism (82, 92, 102) and then flows into the use side heat exchanger (84, 94, 104). The refrigerant flowing into the heat exchanger on the use side (84, 94, 104) is
For example, it absorbs heat from an object to be cooled, such as air in the refrigerator, and evaporates.
The refrigerant evaporated in the use side heat exchangers (84, 94, 104) is returned to the refrigeration system (11) through the communication pipe (17).

In the refrigerating apparatus (11) of the present invention, the refrigerant compressed by the second compressor (31, 32) and the first compressor (33) is sent to the heat source side heat exchanger (34) and the outdoor. It radiates heat to air and condenses. Of the refrigerant discharged from the heat source side heat exchanger (34), the first refrigerant is decompressed by the supercooling expansion mechanism (40) and then introduced into the supercooling heat exchanger (36), and the second refrigerant remains as it is. It is introduced into the supercooling heat exchanger (36). In the supercooling heat exchanger (36), the depressurized first refrigerant absorbs heat from the second refrigerant and evaporates, whereby the second refrigerant is cooled and brought into a supercooled state. Then, the second refrigerant cooled by the supercooling heat exchanger (36) is supplied to the use side units (12, 13, 14) through the communication pipe (16).

Furthermore, in the refrigerating apparatus (11) of the present invention,
The first compressor (33) is capable of sucking the refrigerant evaporated in the supercooling heat exchanger (36). Also, the second
The compressors (31, 32) can suck the refrigerant evaporated in the use side heat exchangers (84, 94, 104). The first compressor (33) provided in this refrigeration system (11) is
There may be one or a plurality of units. Similarly, the second compressor (31, 32) provided in the refrigeration system (11) is
There may be one or a plurality of units.

According to the second aspect of the invention, the refrigeration system (11) is provided with the switching mechanism (25). The switching mechanism (25) is for switching to which of the suction side of the first compressor (33) or the second compressor (31, 32) the subcooling heat exchanger (36) communicates with. is there. In the state where the subcooling heat exchanger (36) communicates with the suction side of the first compressor (33), the refrigerant evaporated in the subcooling heat exchanger (36) is sucked into the first compressor (33). It In a state in which the subcooling heat exchanger (36) communicates with the suction side of the second compressor (31, 32), the refrigerant evaporated in the subcooling heat exchanger (36) is the second compressor (31, 32). ) Is inhaled.

In the refrigeration system (11) of the present invention, even when the first compressor (33) fails, even if the operation of continuing the cooling of the second refrigerant in the subcooling heat exchanger (36) is performed. Good.
That is, if the switching mechanism (25) is switched so that the subcooling heat exchanger (36) communicates with the suction side of the second compressor (31, 32), the subcooling heat exchanger (36) The evaporated first refrigerant is sucked into the second compressor (31, 32), and the second refrigerant is continuously cooled by the supercooling heat exchanger (36).

According to the invention of claim 3, the refrigerating apparatus (11) can perform the following two operations.

One operation is performed when both the first compressor (33) and the second compressor (31, 32) are operating normally. During this operation, the first compressor (33) sucks only the refrigerant evaporated in the subcooling heat exchanger (36), and the second compressor (31, 32) the utilization side heat exchanger (84, 94, 104). ) Inhale only the vaporized refrigerant. Therefore, during this operation, the first
The pressure of the refrigerant sucked into the compressor (33) and the pressure of the refrigerant sucked into the second compressor (31, 32) may be different.

The other operation is performed when the second compressor (31, 32) operates normally but the first compressor (33) fails. During this operation, the first compressor (33)
Heat exchanger (84,94,104), because the operation is not possible
The second compressor (31, 32) sucks both the refrigerant evaporated in (1) and the refrigerant evaporated in the supercooling heat exchanger (36). By performing this operation, even if the first compressor (33) fails, the second refrigerant is continuously cooled by the supercooling heat exchanger (36).

In the fourth aspect of the invention, the refrigeration system (11) is provided with the switching mechanism (26). The switching mechanism (26) is for switching whether the suction side of the first compressor (33) communicates with the subcooling heat exchanger (36) or the utilization side heat exchanger (84, 94, 104). is there. When the suction side of the first compressor (33) is in communication with the supercooling heat exchanger (36), the first compressor (33) sucks the refrigerant evaporated in the supercooling heat exchanger (36). When the suction side of the first compressor (33) communicates with the use side heat exchanger (84, 94, 104), the first compressor (33)
Sucks in the refrigerant evaporated in the use side heat exchanger (84, 94, 104).

In the refrigeration system (11) of the present invention, when the second compressor (31, 32) fails, the utilization side heat exchanger (84, 94, 1)
Operation may be performed in which the cooling of the object to be cooled in 04) is continued. That is, if the switching mechanism (26) is switched so that the suction side of the first compressor (33) communicates with the use side heat exchanger (84, 94, 104), the use side heat exchanger (84, 94, 104).
The refrigerant evaporated in (1) is sucked into the first compressor (33), and the object to be cooled is continuously cooled in the use side heat exchangers (84, 94, 104).

In the fifth aspect of the invention, the refrigeration system (11) can perform the following two operations.

One operation is performed when both the first compressor (33) and the second compressor (31, 32) are operating normally. During this operation, the first compressor (33) sucks only the refrigerant evaporated in the subcooling heat exchanger (36), and the second compressor (31, 32) the utilization side heat exchanger (84, 94, 104). ) Inhale only the vaporized refrigerant. Therefore, during this operation, the first
The pressure of the refrigerant sucked into the compressor (33) and the pressure of the refrigerant sucked into the second compressor (31, 32) may be different.

The other operation is performed when the first compressor (33) operates normally but the second compressor (31, 32) fails. During this operation, the second compressor (31,3
2) is inoperable, so use side heat exchanger (84,94,10
The first compressor (33) sucks the refrigerant evaporated in 4). By performing this operation, even if the second compressor (31, 32) fails, the object to be cooled is continuously cooled by the utilization side heat exchanger (84, 94, 104).

[0028]

Embodiment 1 of the present invention will be described in detail below with reference to the drawings. The present embodiment is a refrigeration / freezing system (1
0), which is installed in a supermarket or the like.

As shown in FIG. 1, the refrigeration / freezing system (10) includes an outdoor unit (11), a first refrigerating unit (12), a second refrigerating unit (13), and a refrigerating unit (1).
4) and a booster unit (15). Then, the first refrigeration unit (12) and the second refrigeration unit (1
3), refrigeration unit (14), and booster unit (1
5) is connected to the outdoor unit (11) by a liquid side communication pipe (16) and a gas side communication pipe (17). In the present embodiment, two refrigerating units (12, 13) and one refrigerating unit (14) are connected to the outdoor unit (11), but the refrigerating units (12, 13) and the refrigerating unit (14) are connected. ) The numbers are only examples.

<< Outdoor Unit >> The outdoor unit (11) is
It constitutes a refrigerating apparatus according to the present invention. The outdoor circuit (30) is housed in the outdoor unit (11). In this outdoor circuit (30), three compressors (31, 32, 33), an outdoor heat exchanger (34), a receiver (35), a supercooling heat exchanger (36), and a four-way A switching valve (39), a first liquid side closing valve (21), and a first gas side closing valve (22) are provided.

Specifically, the outdoor circuit (30) is provided with a first cooling compressor (31), a second cooling compressor (32), and a supercooling compressor (33). There is. These three compressors (31, 32, 33) are all hermetically sealed high-pressure dome type scroll compressors. That is, these compressors (31,3
2, 33), a compression mechanism and an electric motor driving the compression mechanism are housed in a cylindrical casing. Illustration of the compression mechanism and the electric motor is omitted.

Of these compressors (31, 32, 33), the first cooling compressor (31) has a variable capacity in which the rotation speed of the electric motor is changed stepwise or continuously. On the other hand, the second cooling compressor (32) and the supercooling compressor (33) are of a constant capacity in which the electric motor is always driven at a constant rotation speed.
The supercooling compressor (33) constitutes a first compressor, and the first cooling compressor (31) and the second cooling compressor (32) constitute a second compressor. That is, the outdoor unit (11) of the present embodiment is provided with one first compressor and two second compressors.

The discharge sides of the three compressors (31, 32, 33) are connected to the outdoor heat exchanger (34) via the discharge pipes (51). This discharge pipe (51) is 3 at the inlet end side.
It is branched into two branch pipes (51a, 51b, 51c). The first branch pipe (51a) of the discharge pipe (51) is located on the discharge side of the first cooling compressor (31), and the second branch pipe (51b) thereof.
Is connected to the discharge side of the second cooling compressor (32), and its third branch pipe (51c) is connected to the discharge side of the subcooling compressor (33). On the other hand, the outlet end of the discharge pipe (51) is connected to one end of the outdoor heat exchanger (34).

The discharge pipe (51) is provided with an oil separator (63) for separating refrigerating machine oil from the discharge refrigerant. A check valve (CV-2) is provided on the second branch pipe (51b) of the discharge pipe (51).
Is provided. The check valve (CV-2) only allows the refrigerant to flow in the direction in which the refrigerant is discharged from the second cooling compressor (32). A check valve (CV-3) is provided in the third branch pipe (51c) of the discharge pipe (51). This check valve (CV-3)
Only allows the refrigerant to flow in the direction in which the refrigerant is discharged from the subcooling compressor (33).

The outdoor heat exchanger (34) is a cross-fin type fin-and-tube heat exchanger and constitutes a heat source side heat exchanger. This outdoor heat exchanger (34)
The refrigerant discharged from the compressor (31, 32, 33) exchanges heat with the outdoor air and functions as a condenser. Outdoor heat exchanger (34)
The other end of is connected to the receiver (35) via a check valve (CV-4). The check valve (CV-4) only allows the refrigerant to flow from the outdoor heat exchanger (34) to the receiver (35). Further, the receiver (35) is configured by a vertically long and cylindrical hermetic container.

The supercooling heat exchanger (36) is a so-called plate heat exchanger. In this supercooling heat exchanger (36), a plurality of first flow paths (37) and second flow paths (38) are alternately formed with the stacked heat transfer plates sandwiched therebetween. The supercooling heat exchanger (36) is configured to exchange heat between the first refrigerant flowing through the first flow path (37) and the second refrigerant flowing through the second flow path (38). .

In the supercooling heat exchanger (36), the lower end of the first flow path (37) and the upper end of the second flow path (38) are connected to the bottom of the receiver (35), respectively. First flow path (37)
Has a supercooling suction pipe (52) connected to its upper end. The lower end of the second flow path (38) is connected to the first liquid side stop valve (21) via a pipe. In addition, the first channel (3
An expansion valve (40) for supercooling is provided in the pipe connecting the lower end of 7) and the receiver (35). The supercooling expansion valve (40) is a so-called electronic expansion valve and constitutes a supercooling expansion mechanism.

The inlet end of the supercooling suction pipe (52) is connected to the first flow path (37) of the supercooling heat exchanger (36). The supercooling suction pipe (52) is branched into two branch pipes (52a, 52b) at its outlet side end. The supercooling suction pipe (52) is the first branch pipe (52a).
Is connected to the suction side of the supercooling compressor (33), and its second branch pipe (52b) is connected to the four-way switching valve (39). Also,
A check valve (CV-5) is provided on the second branch pipe (52b) of the supercooling suction pipe (52). This check valve (CV-5)
Only the flow of the refrigerant in the direction from the subcooling heat exchanger (36) to the four-way switching valve (39) is allowed.

The inlet end of the main suction pipe (53) is connected to the first gas side stop valve (22). This main suction pipe (53)
Is branched into three branch pipes (53a, 53b, 53c) on the outlet end side. In the main suction pipe (53), the first branch pipe (53a) is on the suction side of the first cooling compressor (31), and the second branch pipe (53b) is in the second cooling compressor (32). ) On the suction side, the third branch pipe (53c) is the supercooling suction pipe (52).
Of the first branch pipe (52a).

A check valve (CV-1) is provided on the third branch pipe (53c) of the main suction pipe (53). This check valve (CV
-1) allows only the refrigerant to flow in the direction from the first gas side stop valve (22) to the supercooling suction pipe (52). The check valve (CV-1) has a state in which the suction side of the subcooling compressor (33) communicates with the subcooling heat exchanger (36) and the suction side of the subcooling compressor (33). A switching mechanism (26) is configured to switch between the state of communicating with the first gas side stop valve (22).

The outdoor circuit (30) is also provided with an injection pipe (61), an oil return pipe (64), and a gas pipe (66). Further, the outdoor circuit (30) is provided with four oil equalizing pipes (67a to 67d).

The injection pipe (61) is for performing so-called liquid injection. An inlet end of the injection pipe (61) is connected to a pipe between the subcooling heat exchanger (36) and the first liquid side stop valve (21),
The outlet end is connected to the main suction pipe (53). Also,
The injection pipe (61) is provided with a flow rate control valve (62).

The oil return pipe (64) has an inlet end connected to the oil separator (63) and an outlet end connected downstream of the flow control valve (62) in the injection pipe (61). The oil return pipe (64) is also provided with an oil return solenoid valve (65). When the oil return solenoid valve (65) is opened and closed appropriately, the refrigerating machine oil separated by the oil separator (63) is sent back to the compressor (31, 32, 33) through the oil return pipe (64).

The gas pipe (66) has a receiver (3
It is connected to the top of 5) and is branched into two branch pipes (66a, 66b) at the other end. This gas pipe (66)
The first branch pipe (66a) is connected to the pipe between the outdoor heat exchanger (34) and the check valve (CV-4), and the second branch pipe (66) is connected to the pipe.
b) is connected to the four-way switching valve (39). A check valve (CV-6) is provided on the first branch pipe (66a) of the gas pipe (66). This check valve (CV-6) is equipped with a gas pipe (66).
Only the circulation of the refrigerant in the direction of flowing out from the receiver (35) is allowed.

The four oil equalizing pipes (67a to 67d) are for equalizing the storage amounts of the refrigerating machine oil in the compressors (31, 32, 33). The inlet end of the first oil leveling pipe (67a) is connected to the first cooling compressor (31), and the outlet end thereof is connected to the second branch pipe (53b) of the main suction pipe (53). A first oil leveling solenoid valve (68a) is provided in the first oil leveling pipe (67a). The second oil equalizing pipe (67b) has an inlet end connected to the second cooling compressor (32) and an outlet end connected to the first branch pipe (52a) of the supercooling suction pipe (52). There is. The second oil level equalizing pipe (67b) includes a second oil leveling solenoid valve (68
b) is provided. An inlet end of the third oil level equalizing pipe (67c) is connected to the supercooling compressor (33) and an outlet end thereof is connected to the first branch pipe (53a) of the main suction pipe (53).
A third oil leveling solenoid valve (68c) is provided in the third oil leveling pipe (67c). The inlet end of the fourth oil level equalizing pipe (67d) is connected between the second cooling compressor (32) and the second oil leveling solenoid valve (68b) in the second oil level equalizing pipe (67b), and its outlet end is connected. It is connected between the third oil leveling solenoid valve (68c) in the third oil leveling pipe (67c) and the first branch pipe (53a) of the main suction pipe (53). The fourth oil level equalizing pipe (67d) includes a fourth oil leveling solenoid valve (68
d) is provided.

The four-way switching valve (39) has a second branch pipe (52b) of the supercooling suction pipe (52) at its first port and a second branch pipe of the gas pipe (66) at its second port. The pipes (51b) are connected to each other. The four-way switching valve (39) has its third port sealed and its fourth port connected to the main suction pipe (53).

The four-way switching valve (39) is in an OFF state in which the first port and the second port communicate with each other and the third port and the fourth port communicate with each other (the state shown by the solid line in FIG. 1). Can be switched to an ON state (state shown by a broken line in FIG. 1) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other. The four-way switching valve (39) has a state in which the subcooling heat exchanger (36) communicates with the suction side of the subcooling compressor (33), and the subcooling heat exchanger (36) has the first and second states. A switching mechanism (25) is configured to switch between the state of communicating with the suction side of the second cooling compressor (31, 32).

The outdoor circuit (30) is also provided with various sensors and pressure switches. Specifically, the discharge pipe (51) is provided with a discharge temperature sensor (72) and a discharge pressure sensor (73). Each branch pipe (51a, 51b, 51) of the discharge pipe (51)
In c), one high pressure switch (74) is provided. The supercooling suction pipe (52) is provided with a supercooling temperature sensor (75) and a supercooling pressure sensor (76). The main suction pipe (53) is provided with a suction temperature sensor (77) and a suction pressure sensor (78). In addition, the outdoor unit (11) includes an outdoor fan (70) and an outdoor air temperature sensor (7
1) and are provided. The outdoor fan (70) sends outdoor air to the outdoor heat exchanger (34).

<< Refrigeration Unit >> First refrigeration unit (12)
The second refrigerating unit (13) is, for example, a showcase for refrigerating and constitutes a user side unit.

A first refrigeration circuit (80) is housed in the first refrigeration unit (12). In the first refrigeration circuit (80),
A first refrigerating electromagnetic valve (81), a first refrigerating expansion valve (82), and a first refrigerating heat exchanger (84) are provided in order from the inlet end to the outlet end. The first refrigeration expansion valve (82) is a so-called automatic temperature expansion valve, and constitutes a utilization side expansion mechanism. The temperature sensing cylinder (83) of the first refrigeration expansion valve (82) is installed on the outlet side of the first refrigeration heat exchanger (84). The first refrigeration heat exchanger (84) is a cross-fin type fin-and-tube heat exchanger,
It constitutes a user side heat exchanger. The first refrigeration heat exchanger (84) functions as an evaporator by exchanging heat between the refrigerant supplied from the outdoor unit (11) and the inside air.

Further, the first refrigerating unit (12) has a first
A refrigeration fan (85) and a first refrigeration temperature sensor (86) are provided. Air in the refrigerator is sent to the first heat exchanger for refrigeration (84) by the first fan for refrigeration (85).
Further, the first refrigeration temperature sensor (86) detects the temperature of the air in the refrigerator sent to the first refrigeration heat exchanger (84).

A second refrigeration circuit (90) is housed in the second refrigeration unit (13). In the second refrigeration circuit (90),
A second refrigerating electromagnetic valve (91), a second refrigerating expansion valve (92), and a second refrigerating heat exchanger (94) are provided in this order from the inlet end to the outlet end. The second refrigeration expansion valve (92) is a so-called automatic temperature expansion valve and constitutes a use side expansion mechanism. The temperature sensing cylinder (93) of the second refrigeration expansion valve (92) is installed on the outlet side of the second refrigeration heat exchanger (94). The second refrigeration heat exchanger (94) is a cross-fin type fin-and-tube heat exchanger,
It constitutes a user side heat exchanger. The second refrigerating heat exchanger (94) functions as an evaporator by exchanging heat between the refrigerant supplied from the outdoor unit (11) and the inside air.

The second refrigeration unit (13) has a second
A refrigeration fan (95) and a second refrigeration temperature sensor (96) are provided. Air in the refrigerator is sent to the second heat exchanger for refrigeration (94) by the second refrigeration fan (95).
Further, the second refrigeration temperature sensor (96) detects the temperature of the in-compartment air sent to the second refrigeration heat exchanger (94).

<< Refrigeration Unit, Booster Unit >> The refrigeration unit (14) is, for example, a showcase for refrigeration, and constitutes a use side unit.

The refrigeration unit (14) includes a refrigeration circuit (10
0) is stored. The refrigeration circuit (100) has a solenoid valve (101) for refrigeration in order from the inlet end to the outlet end.
A freezing expansion valve (102) and a freezing heat exchanger (104). The freezing expansion valve (102) is a so-called temperature automatic expansion valve and constitutes a use side expansion mechanism. The temperature sensing cylinder (103) of the freezing expansion valve (102) is installed on the outlet side of the freezing heat exchanger (104). The freezing heat exchanger (104) is a cross-fin type fin-and-tube heat exchanger, and constitutes a utilization side heat exchanger. This refrigeration heat exchanger (104) includes an outdoor unit (1
It functions as an evaporator by exchanging heat between the refrigerant supplied from 1) and the internal air.

The freezing unit (14) is provided with a freezing fan (105) and a freezing temperature sensor (106). Air in the refrigerator is sent to the heat exchanger for freezing (104) by the freezing fan (105). Further, the freezing temperature sensor (106) detects the temperature of the air in the cold storage sent to the freezing heat exchanger (104).

The booster circuit (110) is housed in the booster unit (15). This booster circuit (110)
A booster compressor (111) is provided in the. The booster compressor (111) is a hermetically sealed, high-pressure dome type scroll compressor. In other words, booster compressor (11
In 1), the compression mechanism and the electric motor that drives it are housed in a cylindrical casing. Illustration of the compression mechanism and the electric motor is omitted. Also, this booster compressor (11
1) is a variable capacity type in which the rotation speed of the electric motor is changed stepwise or continuously.

In the booster circuit (110), an oil separator (112) and a check valve (CV-7) are provided on the discharge side of the booster compressor (111) in order from the upstream side to the downstream side. Has been. The oil separator (112) is a booster compressor (11
It is for separating refrigerating machine oil from the discharge refrigerant of 1) and is connected to the suction side of the booster compressor (111) via a capillary tube (CP). On the other hand, the check valve (C
V-7) allows only the circulation of the refrigerant in the direction discharged from the booster compressor (111).

The booster circuit (110) is also provided with a bypass pipe (113). This bypass pipe (113)
Has its inlet end connected to the suction side of the booster compressor (111) and its outlet end connected to the oil separator (112) and the check valve (CV-
7) connected between. The bypass pipe (113) is also provided with a check valve (CV-8). This check valve (CV
-8) allows only the flow of the refrigerant from the inlet end to the outlet end of the bypass pipe (113).

<< Overall Configuration of Refrigeration / Refrigeration System >> As described above, in the refrigeration / refrigeration system (10) of the present embodiment,
The first refrigerating unit (12), the second refrigerating unit (13), the refrigerating unit (14), and the booster unit (15) are the outdoor unit (11) through the liquid side connecting pipe (16) and the gas side connecting pipe (17). It is connected to the.

The inlet end of the liquid side communication pipe (16) is connected to the first liquid side closing valve (21). This liquid side connection pipe (1
6) is branched into three on the outlet end side, and the first refrigeration circuit (8
0), the second refrigeration circuit (90), and the refrigeration circuit (100). A second liquid side closing valve (23) is provided in a branch pipe of the liquid side communication pipe (16) connected to the refrigeration circuit (100).

The outlet end of the gas side communication pipe (17) is connected to the first gas side shutoff valve (22). The liquid side communication pipe (16) is branched into three on the inlet end side, and the outlet end of the first refrigeration circuit (80), the outlet end of the second refrigeration circuit (90), and the booster circuit (110). It is respectively connected to the outlet end. A second gas side closing valve (24) is provided in a branch pipe of the gas side communication pipe (17) connected to the booster circuit (110). The outlet end of the refrigeration circuit (100) is connected to the inlet end of the booster circuit (110).

In this way, the refrigeration / freezing system (1
In 0), the refrigeration circuit (100) and the booster circuit (110) are connected in series. Then, for the outdoor circuit (30), the first refrigeration circuit (80), the second refrigeration circuit (90), the refrigeration circuit (100) and the booster circuit (110) connected in series.
And are connected in parallel with each other.

-Operational Behavior- The operational behavior of the refrigeration / freezing system (10) will be described. In this refrigeration / freezing system (10), an outdoor unit (11), a refrigeration unit (12, 13) and a refrigeration unit (14)
A refrigerant circulates between and, and a vapor compression refrigeration cycle is performed.

First, the normal operation when all of the first cooling compressor (31), the second cooling compressor (32), and the supercooling compressor (33) can operate normally will be described. During normal operation, the four-way switching valve (39) is in the OFF state (the state shown by the solid line in FIG. 1), and the first subcooling heat exchanger (36)
The flow path (37) communicates with the suction side of the subcooling compressor (33).

During normal operation, the opening degree of the expansion valve (40) for supercooling is controlled. Specifically, the opening degree of the supercooling expansion valve (40) is adjusted according to the degree of superheat of the refrigerant at the outlet of the first flow path (37) of the supercooling heat exchanger (36).
The refrigerant superheat degree at the outlet of the first flow path (37) is detected by the supercooling pressure sensor (76) and the supercooling temperature sensor (75).
It is derived based on the detected value of.

During the normal operation, both the first cooling compressor (31) and the second cooling compressor (32) are not always operating. That is, depending on the load on the refrigeration unit (12, 13) or the refrigeration unit (14), the capacity control of the first cooling compressor (31) and the start / stop of the second cooling compressor (32) are performed. Be seen. Here, in the normal operation, the first cooling compressor (31) and the second cooling compressor (3
2) and the state where all of the supercooling compressor (33) are operating will be described as an example.

The refrigerant discharged from the first cooling compressor (31), the second cooling compressor (32), and the supercooling compressor (33) passes through the discharge pipe (51) to perform outdoor heat exchange. Sent to the container (34). In the outdoor heat exchanger (34), the fed refrigerant radiates heat to outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (34) passes through the receiver (35) and is then split into the first refrigerant and the second refrigerant. The first refrigerant is decompressed by the supercooling expansion valve (40), and then the supercooling heat exchanger (36).
Is introduced into the first flow path (37). On the other hand, the second refrigerant is directly introduced into the second flow path (38) of the subcooling heat exchanger (36).

In the supercooling heat exchanger (36), the first refrigerant in the first flow path (37) and the second refrigerant in the second flow path (38) exchange heat. Then, in the supercooling heat exchanger (36), the first refrigerant absorbs heat from the second refrigerant and evaporates, the second refrigerant is cooled, and the degree of supercooling increases. Supercooling heat exchanger (36)
The first refrigerant evaporated in the first flow path (37) is sucked into the supercooling compressor (33) through the first branch pipe (52a) of the supercooling suction pipe (52). On the other hand, the second refrigerant cooled in the second flow path (38) of the subcooling heat exchanger (36) passes through the first liquid side shutoff valve (21) and flows into the liquid side communication pipe (16). And first
Refrigeration circuit (80), second refrigeration circuit (90), and refrigeration circuit (10
0) and distributed. That is, the heat exchanger for subcooling (36)
The second refrigerant whose enthalpy has been lowered by being cooled by is supplied to the refrigeration unit (12, 13) or the freezing unit (14).

The refrigerant flowing into the first and second refrigeration circuits (80, 90) is decompressed by the first and second refrigeration expansion valves (82, 92), and then the first and second refrigeration heat exchanges. It is introduced into the vessel (84,94). In the first and second heat exchangers for refrigeration (84,94),
The introduced refrigerant absorbs heat from the inside air and evaporates, and the inside air is cooled. First and second refrigeration heat exchangers (84,94)
The refrigerant evaporated in (1) is sent out from the first and second refrigeration circuits (80, 90) to the gas side communication pipe (17).

On the other hand, the refrigerant flowing into the refrigeration circuit (100) through the second liquid side closing valve (23) is decompressed by the refrigeration expansion valve (102) and then to the refrigeration heat exchanger (104). be introduced. In the freezing heat exchanger (104), the introduced refrigerant absorbs heat from the inside air and evaporates, so that the inside air is cooled. The refrigerant evaporated in the freezing heat exchanger (104) is drawn into the booster compressor (111) of the booster circuit (110) and compressed. The refrigerant compressed by the booster compressor (111) is sent out from the booster circuit (110) to the gas side communication pipe (17).

The refrigerant evaporated in the first and second refrigerating heat exchangers (84, 94) and the refrigerant evaporated in the freezing heat exchanger (104) and compressed by the booster compressor (111) are They join together in the gas side communication pipe (17) and flow into the main suction pipe (53) through the first gas side stop valve (22). A part of the refrigerant flowing into the main suction pipe (53) passes through the first branch pipe (53a) and is sucked into the first cooling compressor (31), and the rest of the refrigerant flows into the second branch pipe (53).
It is drawn into the second cooling compressor (32) through b).

As described above, during the normal operation, the subcooling compressor (33) sucks only the refrigerant evaporated in the first flow path (37) of the subcooling heat exchanger (36), The first and second cooling compressors (31, 32) suck only the refrigerant evaporated in the refrigerating heat exchanger (84, 94) and the freezing heat exchanger (104). Then, during this normal operation, the refrigerant evaporation temperature in the subcooling heat exchanger (36) is set higher than the refrigerant evaporation temperature in the refrigeration heat exchanger (84, 94).

Next, although the first cooling compressor (31) and the second cooling compressor (32) are functioning normally, the first cooling compressor (33) fails The backup operation will be described. During this operation, the four-way selector valve (3
9) is turned on (the state shown by the broken line in FIG. 1), and the first flow path (37) of the supercooling heat exchanger (36) is connected to the main suction pipe (53).
Communicate with. In addition, during this operation, the opening degree of the subcooling expansion valve (40) is controlled in the same manner as during normal operation. Here, the difference in the operation during the first backup operation from that during the normal operation will be described.

During the first backup operation, since the subcooling compressor (33) cannot be operated, only the first cooling compressor (31) and the second cooling compressor (32) are operated.
However, during this operation as well as during normal operation,
Capacity control of the first cooling compressor (31) and start / stop of the second cooling compressor (32) are performed. That is, both the first cooling compressor (31) and the second cooling compressor (32) do not always operate.

In the first backup operation,
The first refrigerant evaporated in the first flow path (37) of the subcooling heat exchanger (36) flows into the main suction pipe (53) through the four-way switching valve (39), and the refrigeration heat exchanger ( 84,94) and heat exchangers for refrigeration (1
It merges with the second refrigerant evaporated in 04). Then, the first refrigerant flowing into the main suction pipe (53) is sucked into the first cooling compressor (31) and the second cooling compressor (32) together with the second refrigerant.

That is, during the first backup operation, the first cooling compressor (31) and the second cooling compressor (32)
Sucks both the first refrigerant evaporated in the supercooling heat exchanger (36) and the second refrigerant evaporated in the refrigerating heat exchanger (84, 94) and the freezing heat exchanger (104). . Therefore, by performing this operation, even if the subcooling compressor (33) fails, the second refrigerant in the subcooling heat exchanger (36) is continuously cooled.

Then, the first cooling compressor (31) or the second cooling compressor (31)
The second backup operation when the cooling compressor (32) is out of order will be described. During this operation, the four-way switching valve (39) is in the OFF state (the state shown by the solid line in FIG. 1), and the first flow path (37) of the subcooling heat exchanger (36) has the subcooling compressor (33). Communicate with the intake side of. Further, during this operation, the subcooling expansion valve (40) is fully closed. Here, differences in the operation during the second backup operation from those during the normal operation will be described.

As described above, during the second backup operation, the subcooling expansion valve (40) is fully closed. Therefore,
In the subcooling heat exchanger (36), all of the refrigerant discharged from the receiver (35) is sent to the second flow path (38),
No refrigerant is supplied to the first flow path (37). Then, the refrigerant discharged from the receiver (35) is used as a subcooling heat exchanger (36).
It simply passes through the second flow path (38) and is discharged to the liquid side communication pipe (16) without being cooled.

During the second backup operation, the second backup
Assuming that the cooling compressor (32) is out of order,
Only the cooling compressor (31) and the supercooling compressor (33) are operated. In this operation, the capacity of the first cooling compressor (31) may be controlled and the supercooling compressor (33) may be started and stopped.

During the second backup operation, the refrigerant evaporated in the refrigerating heat exchangers (84, 94) and the freezing heat exchanger (104) flows from the gas side communication pipe (17) to the main suction pipe (53).
Flow into. Then, a part of the refrigerant flowing into the main suction pipe (53) passes through the first branch pipe (53a) of the main suction pipe (53) and is sucked into the first cooling compressor (31), and the rest is left. From the third branch pipe (53c) of the main suction pipe (53) to the supercooling suction pipe (5
Compressor (33) for supercooling through the first branch pipe (52a) of 2)
Inhaled into. Therefore, if this operation is performed, even if the first cooling compressor (31) or the second cooling compressor (32) fails, the refrigeration heat exchanger (84, 94) and the refrigeration heat The air in the cold storage in the exchanger (104) is continuously cooled.

Here, even when both the first cooling compressor (31) and the second cooling compressor (32) are out of order, the second
The same operation as the backup operation is performed. That is, the four-way switching valve (39) is turned off and the subcooling expansion valve (40) is fully closed. Then, only the subcooling compressor (33) is operated, and the refrigerant evaporated in the refrigeration heat exchangers (84, 94) and the freezing heat exchanger (104) is sucked into the subcooling compressor (33). It

-Effects of Embodiment 1- In the outdoor unit (11) of this embodiment, the second refrigerant is cooled by exchanging heat with the first refrigerant in the supercooling heat exchanger (36), and after cooling. Refrigerating unit for the second refrigerant (12,1
3) and the refrigeration unit (14). That is, as compared with the case where the refrigerant condensed in the outdoor heat exchanger (34) is directly supplied to the refrigerating unit (12, 13) or the refrigerating unit (14), the refrigerant having a lower enthalpy is refrigerated (12, 1).
3) and the refrigeration unit (14). For this reason,
The heat exchangers for refrigeration (84,94) and the heat exchanger for freezing (84,94) and the heat exchanger for freezing (without increasing the refrigerant circulation amount between the refrigerating unit (12,13) or freezing unit (14) and the outdoor unit (11) so much. 104)
The refrigerating capacity can be increased by increasing the enthalpy difference of the refrigerant at the inlet and outlet of the.

As described above, according to this embodiment, a larger refrigerating capacity can be obtained without increasing the flow rate of the refrigerant flowing through the liquid side communication pipe (16) and the gas side communication pipe (17). . Even if the outdoor unit (11) is connected to the usage-side unit by using the existing relatively thin connection pipe, it is possible to prevent the refrigerant pressure loss in the connection pipe from increasing and the refrigeration capacity to decrease. it can. Therefore, according to the present embodiment, by diverting the existing communication pipes (16, 17) to reduce the cost required for installing the outdoor unit (11) and shorten the construction period, the outdoor unit (11) The freezing capacity of can be surely exhibited.

Further, the outdoor unit (11) of this embodiment.
Is the first and second cooling compressors (3
1,32) are heat exchangers for refrigeration (84,94) and heat exchangers for freezing (1
Only the refrigerant evaporated in 04) is sucked in and the supercooling compressor (3
3) is configured to suck only the refrigerant evaporated in the subcooling heat exchanger (36). Therefore, the first and second cooling compressors (31, 32) have the highest efficiency when the suction pressure thereof matches the refrigerant evaporation pressure set in the refrigeration heat exchangers (84, 94). You can select a compressor with the following specifications. Similarly, for the supercooling compressor (33), select a compressor that has the highest efficiency when the suction pressure matches the refrigerant evaporation pressure set in the supercooling heat exchanger (36). it can. Therefore, according to the present embodiment, it is possible to adopt a compressor having optimum specifications for each of the first and second cooling compressors (31, 32) and the supercooling compressor (33), and refrigerate. -The efficiency of the refrigeration system (10) can be improved.

Further, the outdoor unit (11) of this embodiment
Are configured to enable the first backup operation. By performing the first backup operation, even if the subcooling compressor (33) fails, the second refrigerant in the subcooling heat exchanger (36) is continuously cooled. You can That is, even when the subcooling compressor (33) is out of order, a refrigerant having a large degree of subcooling and a low enthalpy is supplied to the refrigeration unit (12, 13) or the refrigeration unit (14). You can According to this embodiment,
The same operation as during normal operation can be continued even when the supercooling compressor (33) is out of order, and the reliability of the refrigeration / freezing system (10) can be improved.

Further, the outdoor unit (11) of this embodiment.
Are configured so that the second backup operation is possible. By performing the second backup operation, even if the first cooling compressor (31) or the second cooling compressor (32) fails, the refrigeration unit (12, 13) or the refrigeration unit. The air in the refrigerator in (14) can be continuously cooled. That is, the first cooling compressor (31) and the second
Even if the cooling compressor (32) is out of order, it is possible to suppress the temperature rise of the showcase, which is the refrigeration unit (12, 13) or the freezing unit (14). Therefore, according to the present embodiment, the first cooling compressor (31) and the second cooling compressor (32).
It is possible to prevent the foodstuffs and the like in the showcase from being damaged even during the failure of, and to improve the reliability of the refrigeration / freezing system (10).

[0088]

Second Embodiment A second embodiment of the present invention is the same as the outdoor unit (11) of the first embodiment, except that the outdoor circuit (3
This is a modification of the configuration in (0). Here, with respect to the outdoor circuit (30) of the present embodiment, differences from the above-described first embodiment will be described.

As shown in FIG. 2, in the outdoor circuit (30) of this embodiment, the suction side of the subcooling compressor (33) communicates with the subcooling heat exchanger (36) and the subcooling is performed. Compressor (3
Only the switching mechanism (26) for switching the state of the suction side of 3) communicating with the first gas side closing valve (22) is provided. In the outdoor circuit (30), the four-way switching valve (39) and the supercooling expansion valve (40) constitute this switching mechanism (26).

In the outdoor circuit (30) of this embodiment, the supercooling suction pipe (52) is connected to the suction side of the subcooling compressor (33) without being branched at the outlet end side. The third branch pipe (53c) of the main suction pipe (53) is connected to the four-way switching valve (39). This four-way switching valve (39)
A third branch pipe (53) of the main suction pipe (53) is connected to the first port.
In c), the second branch pipes (51b) of the gas pipes (66) are connected to the second ports thereof. The four-way switching valve (39) has a third port sealed and a fourth port connected to the supercooling suction pipe (52).

The four-way switching valve (39) has a first port and a second port.
State in which all ports are in communication with each other and the third port and the fourth port are in communication with each other (state shown by a solid line in FIG. 2)
And the first port and the fourth port communicate with each other and the second port
ON state in which the port and the third port communicate with each other (Fig. 2
It is possible to switch to the state shown by the broken line in FIG. This point is the same as the first embodiment.

In the refrigerating / freezing system (10) of this embodiment, the normal operation and the second backup operation can be performed as in the case of the above-mentioned first embodiment. However, refrigeration of this embodiment
The first backup operation cannot be performed in the refrigeration system (10).

During normal operation, the four-way switching valve (39) is OF
The F state (the state shown by the solid line in FIG. 2) is set. In this state, the four-way switching valve (39) shuts off the connection between the main suction pipe (53) and the supercooling suction pipe (52), and the supercooling compressor (33).
The suction side of is communicated only with the first flow path (37) of the subcooling heat exchanger (36). In addition, during normal operation, the opening degree of the supercooling expansion valve (40) is adjusted according to the degree of superheat of the refrigerant at the outlet of the first flow path (37) of the supercooling heat exchanger (36). Then, in the refrigeration / freezing system (10) of the present embodiment, as in the normal operation of the first embodiment, the outdoor unit (11), the refrigeration unit (12, 13) and the freezing unit (1).
Refrigerant circulates with 4) to perform a vapor compression refrigeration cycle.

On the other hand, during the second backup operation, the four-way switching valve (39) is in the ON state (the state shown by the broken line in FIG. 2), and the supercooling expansion valve (40) is in the fully closed state. In this state, the supercooling compressor (33) is passed through the four-way switching valve (39).
The suction side of which is communicated with the main suction pipe (53), and the expansion valve (40) for supercooling causes the first flow path (3) of the heat exchanger (36) for supercooling.
Refrigerant flow into 7) is blocked. Then, in the refrigerating / refrigerating system (10) of the present embodiment, the outdoor unit (11) and the refrigerating unit (12, 13) and the refrigerating unit (14) are connected to each other as in the second backup operation of the first embodiment. A refrigerant circulates between them to perform a vapor compression refrigeration cycle.

[0095]

Third Embodiment A third embodiment of the present invention is the same as the outdoor unit (11) of the first embodiment, except that the outdoor circuit (3
This is a modification of the configuration in (0). Here, with respect to the outdoor circuit (30) of the present embodiment, differences from the above-described first embodiment will be described.

As shown in FIG. 3, in the outdoor circuit (30) of this embodiment, the suction side of the subcooling compressor (33) communicates with the subcooling heat exchanger (36) and the subcooling is performed. Compressor (3
Only the switching mechanism (26) for switching the state of the suction side of 3) communicating with the first gas side closing valve (22) is provided. In the outdoor circuit (30), the four-way switching valve (39) constitutes this switching mechanism (26).

In the outdoor circuit (30) of this embodiment, the subcooling heat exchanger (36) and the subcooling compressor (33) are the first
They are connected by a supercooling suction pipe (54) and a second supercooling suction pipe (55).

The inlet port of the first supercooling suction pipe (54) is connected to the upper end of the first flow path (37) of the supercooling heat exchanger (36), and the outlet port thereof is a four-way switching valve ( 39) is connected to. A supercooling temperature sensor (75) is attached to the first supercooling suction pipe (54). A check valve (CV-9) is provided in the first supercooling suction pipe (54). The check valve (CV-9) allows only the flow of the refrigerant in the direction from the subcooling heat exchanger (36) to the four-way switching valve (39).

On the other hand, the second supercooling suction pipe (55) has its inlet end connected to the four-way switching valve (39) and its outlet end connected to the suction side of the supercooling compressor (33). There is. The second supercooling suction pipe (55) has a supercooling pressure sensor (7
6) is installed. The third branch pipe (53c) of the main suction pipe (53) is connected to the four-way switching valve (39).

In the outdoor circuit (30) of this embodiment, the four-way switching valve (39) has the first supercooling suction pipe (54) at its first port and the second subcooling at its second port. Intake pipe (55), the third port thereof has a third branch pipe (53c) of the main intake pipe (53), and the fourth port thereof has a second branch pipe (66b) of a gas pipe (66). Each is connected.

The four-way switching valve (39) is in an OFF state in which the first port and the second port communicate with each other and the third port and the fourth port communicate with each other (state shown by a solid line in FIG. 3). Can be switched to an ON state (state shown by a broken line in FIG. 3) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other. This point is the same as the first embodiment.

In the refrigerating / freezing system (10) of this embodiment, the normal operation and the second backup operation can be performed as in the case of the above-mentioned first embodiment. However, refrigeration of this embodiment
The first backup operation cannot be performed in the refrigeration system (10).

During normal operation, the four-way switching valve (39) is OF
The F state (the state shown by the solid line in FIG. 3) is set. In this state, the four-way switching valve (39) causes the first subcooling suction pipe (5
4) is in communication with the second supercooling suction pipe (55), and the suction side of the supercooling compressor (33) is the first subcooling heat exchanger (36).
It communicates only with the flow path (37). In addition, during normal operation, the opening degree of the supercooling expansion valve (40) is adjusted according to the degree of superheat of the refrigerant at the outlet of the first flow path (37) of the supercooling heat exchanger (36). Then, in the refrigeration / freezing system (10) of the present embodiment, the outdoor unit (11) and the refrigeration unit (12, 13) or the freezing unit (14) are connected between the outdoor unit (11) and the refrigeration unit (14) as in the normal operation of the first embodiment. The refrigerant circulates to perform the vapor compression refrigeration cycle.

On the other hand, during the second backup operation, the four-way switching valve (39) is turned on (the state shown by the broken line in FIG. 3), and the supercooling expansion valve (40) is fully closed. In this state, the four-way switching valve (39) is connected to the main suction pipe (53) and the second
The supercooling suction pipe (55) is made to communicate with each other, and at the same time, the first supercooling suction pipe (54) and the second supercooling suction pipe (55) are cut off from each other. That is, the connection destination on the suction side of the supercooling compressor (33) is switched from the first supercooling suction pipe (54) to the main suction pipe (53). Then, in the refrigeration / freezing system (10) of the present embodiment, the outdoor unit (11) and the refrigeration unit (1) as in the second backup operation of the first embodiment.
2, 13) and the refrigeration unit (14) circulate a refrigerant to perform a vapor compression refrigeration cycle.

[0105]

Fourth Embodiment of the Invention The second embodiment of the present invention is the same as the outdoor unit (11) of the first embodiment, except that the outdoor circuit (3
This is a modification of the configuration in (0). Here, with respect to the outdoor circuit (30) of the present embodiment, differences from the above-described first embodiment will be described.

As shown in FIG. 4, in the outdoor circuit (30) of the present embodiment, the suction side of the subcooling compressor (33) communicates with the subcooling heat exchanger (36) and the subcooling is performed. Compressor (3
Only the switching mechanism (26) for switching the state of the suction side of 3) communicating with the first gas side closing valve (22) is provided. In the outdoor circuit (30), the third main suction pipe (53)
The check valve (CV-1) provided in the branch pipe (53c) and the supercooling expansion valve (40) constitute this switching mechanism (26).

In the outdoor circuit (30) of the present embodiment, the supercooling suction pipe (52) is connected to the suction side of the supercooling compressor (33) without being branched at the outlet end side. Further, in this outdoor circuit (30), the four-way switching valve (39) and the gas pipe (66) are omitted, and a communication pipe (69) is added. One end of the communication pipe (69) is connected to the upstream side of the flow rate control valve (62) in the injection pipe (61).
The other end is connected to the pipe between the outdoor heat exchanger (34) and the check valve (CV-4). In addition, this communication pipe (69),
A check valve (CV-10) is provided. This check valve (CV-1
0) allows only the flow of the refrigerant in the direction from one end of the communication pipe (69) to the other end.

In the refrigerating / refrigerating system (10) of the present embodiment, the normal operation and the second backup operation can be performed as in the case of the above-mentioned Embodiment 1. However, refrigeration of this embodiment
The first backup operation cannot be performed in the refrigeration system (10).

During normal operation, the expansion valve (4
The opening degree of (0) corresponds to the first flow path (3) of the subcooling heat exchanger (36).
7) Adjusted according to the degree of superheat of the refrigerant at the outlet. Further, since the refrigerant evaporation pressure in the supercooling heat exchanger (36) is higher than the refrigerant evaporation pressure in the refrigeration heat exchanger (84,94),
The check valve (CV-1) provided in the third branch pipe (53c) of the main suction pipe (53) is closed. In this state, the check valve (CV-1) uses the main suction pipe (53) and the supercooling suction pipe (5
2) is cut off, and the suction side of the subcooling compressor (33) communicates only with the first flow path (37) of the subcooling heat exchanger (36). Then, in the refrigeration / freezing system (10) of the present embodiment, as in the normal operation of the first embodiment, the outdoor unit (11), the refrigeration unit (12, 13) and the freezing unit (1).
Refrigerant circulates with 4) to perform a vapor compression refrigeration cycle.

On the other hand, during the second backup operation, the supercooling expansion valve (40) is fully closed. In this state, the check valve (CV-1) provided in the third branch pipe (53c) of the main suction pipe (53) is in a communication state, and the suction side of the subcooling compressor (33) is connected to the main suction pipe (53). 53). Further, the supercooling expansion valve (40) in the fully closed state allows the supercooling heat exchanger (36).
The refrigerant is prevented from flowing into the first flow path (37). Then, in the refrigerating / refrigerating system (10) of the present embodiment, the outdoor unit (11) and the refrigerating unit (12, 13) and the refrigerating unit (14) are connected to each other as in the second backup operation of the first embodiment. A refrigerant circulates between them to perform a vapor compression refrigeration cycle.

[0111]

Other Embodiments of the Invention In each of the above embodiments,
The outdoor unit (11) is connected to the refrigeration unit (12, 13) or the freezing unit (14) to form the refrigeration / freezing system (10), but the outdoor unit (11) is connected to the indoor unit of the air conditioner. The air-conditioning system may be configured. In this case, the configuration of the outdoor unit (11) may be changed so that the indoor unit can perform both the cooling operation and the heating operation. However, in that case, the cooling of the second refrigerant in the subcooling heat exchanger (36) is performed only during the cooling operation. In addition, the outdoor unit (11) is connected not only to the refrigeration unit (12, 13) and the freezing unit (14) but also to the indoor unit of the air conditioner to form a refrigeration / freezing system (10) capable of air conditioning. Good.

[0112]

In the refrigeration system according to the present invention, the second refrigerant is cooled by exchanging heat with the first refrigerant in the supercooling heat exchanger (36), and the cooled second refrigerant is used by the unit ( 12, 13, 14). That is, the refrigerant condensed in the heat source side heat exchanger (34) is used as it is in the use side unit (12,1).
Refrigerant with a lower enthalpy is supplied to the usage-side unit (12, 13, 14) than when it is supplied to the unit (12, 13, 14). Therefore, even if the refrigerant circulation amount between the refrigeration system and the use side units (12, 13, 14) is not increased so much, the use side heat exchanger (8
The refrigerating capacity can be increased by enlarging the enthalpy difference of the refrigerant at the inlet and outlet (4,94,104).

As described above, according to the present invention, a greater refrigerating capacity can be exhibited in the refrigerating apparatus without increasing the flow rate of the refrigerant flowing in the communication pipe so much.
Therefore, even if the refrigeration equipment is connected to the use side units (12, 13, 14) using the existing communication pipes,
It is possible to avoid a decrease in refrigerating capacity due to an increase in pressure loss of the refrigerant in the connecting pipe. Therefore, according to the present invention, by diverting the existing communication pipes (16, 17) to reduce the cost required for the installation of the refrigeration system (11) and the construction period, the refrigeration system (11) The refrigerating capacity can be surely exhibited.

According to the second and third aspects of the invention, even if the first compressor (33) fails, the refrigerant evaporated in the subcooling heat exchanger (36) is used as the second compressor. The second refrigerant in the supercooling heat exchanger (36) can be cooled by sucking it into (31, 32). Further, according to the inventions of claim 4 and claim 5, even when the second compressor (31, 32) fails, the refrigerant evaporated in the utilization side heat exchanger (84, 94, 104) By inhaling into the compressor (33),
The object to be cooled in the utilization side heat exchanger (84, 94, 104) can be cooled. Therefore, according to these inventions, the operation of the refrigeration system can be continued even if any of the compressors fails, and the reliability of the refrigeration system can be improved.

[Brief description of drawings]

FIG. 1 is a piping system diagram of a refrigeration / freezing system according to a first embodiment.

FIG. 2 is a piping system diagram of a refrigeration / freezing system according to a second embodiment.

FIG. 3 is a piping system diagram of a refrigeration / freezing system according to a third embodiment.

FIG. 4 is a piping system diagram of a refrigeration / refrigeration system according to a fourth embodiment.

[Explanation of symbols]

(11) Outdoor unit (refrigerator) (12) First refrigeration unit (user side unit) (13) Second refrigeration unit (user side unit) (14) Refrigeration unit (user side unit) (25) Switching mechanism (26) Switching mechanism (31) First cooling compressor (second compressor) (32) Second cooling compressor (second compressor) (33) Compressor for supercooling (first compressor) (34) Outdoor heat exchanger (heat source side heat exchanger) (36) Heat exchanger for supercooling (40) Supercooling expansion valve (supercooling expansion mechanism) (82) 1st refrigeration expansion valve (use side expansion mechanism) (84) First refrigeration heat exchanger (use side heat exchanger) (92) Second refrigeration expansion valve (use side expansion mechanism) (94) Second refrigeration heat exchanger (use side heat exchanger) (102) Freezing expansion valve (use side expansion mechanism) (104) Refrigeration heat exchanger (use side heat exchanger)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F25B 41/04 F25B 41/04 E (72) Inventor Kenji Tanimoto 1304 Kanaoka-cho, Sakai-shi, Osaka Daikin Industries Ltd. Sakai Factory Kanaoka Factory

Claims (5)

[Claims] 1. A utilization side heat exchanger (84, 94, 10) which serves as an evaporator.
4) and a use side unit (12, 13, 14) having a use side expansion mechanism (82, 92, 102) for depressurizing the supplied refrigerant
A refrigerating device that is connected to the above-mentioned use side unit (12, 13, 14) through a communication pipe (16, 17) and circulates a refrigerant between the user side unit (12, 13, 14) to perform a refrigerating cycle. A heat exchanger (34), a supercooling expansion mechanism (40) for decompressing the first refrigerant, which is a part of the refrigerant discharged from the heat source side heat exchanger (34), and the first refrigerant being divided. The second refrigerant, which is the remaining refrigerant after being cooled and is supplied to the use side unit (12, 13, 14), is heat-exchanged with the first refrigerant whose pressure is reduced by the expansion mechanism (40) for supercooling. A subcooling heat exchanger (36) for cooling, a first compressor (33) capable of sucking the refrigerant evaporated in the subcooling heat exchanger (36), and a utilization side heat exchanger (84) , 94, 104) and a second compressor (31, 32) capable of sucking the refrigerant evaporated in (94, 104). 2. The refrigeration system according to claim 1, wherein the subcooling heat exchanger (36) communicates with a suction side of the first compressor (33) and the subcooling heat exchanger (36). A refrigeration system comprising a switching mechanism (25) for switching between a state in which the second compressor (31, 32) communicates with the suction side. 3. The refrigeration apparatus according to claim 1, wherein the first compressor (33) sucks only the refrigerant evaporated in the supercooling heat exchanger (36), and the second compressor (31, 32) Operation in which only the refrigerant evaporated in the use side heat exchanger (84, 94, 104) is taken in, and when the first compressor (33) fails, the second compressor (31, 3)
The refrigerating device configured such that 2) can perform an operation of sucking both the refrigerant evaporated in the use side heat exchanger (84, 94, 104) and the refrigerant evaporated in the supercooling heat exchanger (36). 4. The refrigeration apparatus according to claim 1, wherein the suction side of the first compressor (33) communicates with the subcooling heat exchanger (36) and the suction side of the first compressor (33) is used. A refrigeration system provided with a switching mechanism (26) for switching between a state in which the side heat exchangers (84, 94, 104) communicate with each other. 5. The refrigeration apparatus according to claim 1, wherein the first compressor (33) sucks only the refrigerant evaporated in the supercooling heat exchanger (36), and the second compressor (31, 32) In the operation in which only the refrigerant evaporated in the use side heat exchanger (84, 94, 104) is taken in, and when the second compressor (31, 32) fails, the first compressor (3
Refrigeration system configured so that 3) can be operated so as to suck in the refrigerant evaporated in the heat exchangers (84, 94, 104) on the use side.