WO2006019074A1

WO2006019074A1 - Freezing apparatus

Info

Publication number: WO2006019074A1
Application number: PCT/JP2005/014911
Authority: WO
Inventors: Masaaki Takegami; Satoru Sakae; Kenji Tanimoto
Original assignee: Daikin Industries, Ltd.
Priority date: 2004-08-17
Filing date: 2005-08-15
Publication date: 2006-02-23
Also published as: CN101014818A; JP2006057869A; CN100458312C

Abstract

A heat exchanger (45) for air conditioning, in which indoor cooling and heating are switched between each other, is provided only in a high-stage-side refrigerant circuit (8). On the other hand, heat exchangers (47a, 47b, 49) for cooling, which cool inside a cold storage, are provided only in a low-stage-side refrigerant circuit (9).

Description

Specification

Refrigeration equipment

Technical field

[0001] The present invention relates to a refrigeration apparatus in which a high-stage refrigerant circuit and a low-stage refrigerant circuit are connected via a cascade heat exchanger to perform a dual refrigeration cycle.

2. Description of the Related Art Conventionally, a refrigeration apparatus that is applied to, for example, a convenience store and simultaneously performs indoor air-conditioning and cooling in a refrigerator or a freezer is known. As such a refrigeration apparatus, there is an apparatus in which a high-stage refrigerant circuit and a low-stage refrigerant circuit are connected via a cascade heat exchange to perform a dual refrigeration cycle.

For example, the refrigeration apparatus disclosed in Patent Document 1 includes an air conditioning heat exchanger that performs indoor air conditioning and a cooling heat exchanger that cools the interior of the refrigerator. The cooling heat exchanger is composed of a refrigeration heat exchanger that cools the inside of the cabinet and a refrigeration heat exchanger that freezes the inside of the cabinet.

[0003] An air conditioning circuit and a refrigeration circuit are connected in parallel to the high-stage refrigerant circuit of the refrigeration apparatus. The air conditioning circuit includes the air conditioning heat exchanger that switches between indoor cooling and heating. On the other hand, the refrigeration circuit is provided with a plurality of refrigeration heat exchangers for cooling the refrigerator. The high-stage refrigerant circuit is connected to a high-stage compressor, an outdoor heat exchanger, a first heat exchange section of the cascade heat exchanger, and an expansion valve. On the other hand, the low-stage refrigerant circuit is connected to a refrigeration heat exchanger that performs refrigeration in the freezer, a low-stage compressor, a second heat exchange section of the cascade heat exchanger, and an expansion valve.

[0004] In the refrigeration apparatus configured as described above, for example, during indoor heating operation, the air conditioning heat exchanger serves as a condenser to heat indoor air, while the refrigeration heat exchanger and the refrigeration heat exchanger include It becomes an evaporator and cools the air in the refrigerator and the freezer. Here, this refrigeration apparatus transfers the heat absorbed by the refrigeration heat exchanger to the high-stage refrigerant circuit via the cascade heat exchanger, and uses this heat for heating the heat exchanger for air conditioning. . That is, in this refrigeration apparatus, heat from the low-stage refrigerant circuit side is recovered by the cascade heat exchanger on the high-stage refrigerant circuit side, and this heat is used for heating operation. Patent Document 1: Japanese Patent Laid-Open No. 2002-181406

Disclosure of the invention

Problems to be solved by the invention

[0005] As described above, the refrigeration apparatus of Patent Document 1 uses an air conditioning heat exchanger, a refrigeration heat exchanger, and a refrigeration heat exchanger as a use side for indoor air conditioning and internal cooling ( Refrigeration Z freezing) can be performed at the same time. By the way, for example, the cooling temperature of the heat exchange for air conditioning during the cooling operation is in a range from about 20 ° C. to 30 ° C., for example, while the refrigeration temperature in the refrigerator performed by the refrigeration heat exchanger is, for example, The range is from 0 ° C to 10 ° C, and the usage temperature range of each is very different. On the other hand, the air-conditioning heat exchanger ^^ and the refrigeration heat exchanger ^^, which have different usage temperature ranges, are connected to a high-stage refrigerant circuit that is a closed circuit in which the same refrigerant flows. . For this reason, it is necessary to evaporate the same refrigerant at different temperatures in the heat exchanger for air conditioning and the heat exchanger for refrigeration. As a result, the problem is that the temperature control of the refrigerant in each heat exchanger becomes complicated.

[0006] This problem is related to the heat exchanger for air conditioning ^^ and the heat exchanger for refrigeration, which have different usage temperature ranges.

Is more prominent when connected to the higher-stage refrigerant circuit. As described above, there is a demand for a refrigeration apparatus that can easily perform temperature control between an air conditioning heat exchanger and a refrigeration Z refrigeration heat exchanger (cooling heat exchanger) having different utilization temperature ranges.

[0007] The present invention was devised in view of such problems, and an object of the present invention is to provide a heat exchanger for air conditioning that performs air conditioning and cooling in a warehouse in a refrigeration apparatus that performs a dual refrigeration cycle. This is to make it easy to control the temperature with the cooling heat exchanger.

Means for solving the problem

In the present invention, the air conditioner heat exchanger is provided only in the high stage side refrigerant circuit, while the cooling heat exchanger is provided only in the low stage side refrigerant circuit.

[0009] More specifically, in the first invention, a high-stage refrigerant circuit (8) and a low-stage refrigerant circuit (9) are connected via a cascade heat exchange (40) to form a binary circuit. It assumes a refrigeration system that performs a refrigeration cycle and has heat exchange for air conditioning (45) that switches between indoor cooling and heating and cooling heat exchange (47a, 47b, 49) that cools the interior of the refrigerator. . And this refrigeration apparatus The conditioning heat exchanger (45) is provided only in the high-stage refrigerant circuit (8), while the cooling heat exchanger (47a, 47b, 49) is provided in the low-stage refrigerant circuit (9). It is only provided.

[0010] In the first invention, the refrigeration cycle is performed in the high-stage refrigerant circuit (8) serving as a closed circuit, and at the same time, another refrigeration cycle is performed in the low-stage refrigerant circuit (9) serving as a closed circuit. The so-called dual refrigeration cycle is performed.

Specifically, in the cooling heat exchangers (47a, 47b, 49), the refrigerant absorbs heat from the air in the warehouse and evaporates. That is, the cooling heat exchange m ^ (47a, 47b, 49) functions as an evaporator. On the other hand, in the air conditioner heat exchanger (45), during cooling, the refrigerant also absorbs the aerodynamic force of the room and evaporates. That is, during cooling, the air conditioning heat exchanger (45) functions as an evaporator. In the heat exchanger for air conditioning (45), during heating, the refrigerant dissipates heat to the indoor air and condenses. That is, during heating, the air conditioning heat exchanger (45) functions as a condenser. Here, at the time of heating, in the cascade heat exchanger (40), the heat of the refrigerant in the low stage side refrigerant circuit (9) that has absorbed heat from the air in the cabinet is recovered to the refrigerant in the high stage side refrigerant circuit (8). The In the high-stage refrigerant circuit (8), the heat recovered as described above is used for indoor heating.

[0012] Here, in the present invention, the air-conditioning heat exchanger (45) that cools and heats the room is replaced with a high-stage refrigerant circuit.

On the other hand, a cooling heat exchanger (47a, 47b, 49) for cooling the inside of a refrigerator or a freezer is provided only in the low-stage refrigerant circuit (9). Therefore, the air conditioner heat exchanger (45) and the cooling heat exchanger (47a, 47b, 49) can be provided in different closed circuits.

[0013] As described above, when the heat exchanger for air conditioning (45) and the heat exchanger for cooling (47a, 47b, 49) are provided in different closed circuits, different refrigerants can be supplied to the respective heat exchangers. . Therefore, a refrigerant suitable for indoor air conditioning by the air conditioner heat exchanger (45) is circulated in the high-stage refrigerant circuit (8) to perform a refrigeration cycle, and at the same time, unlike this refrigerant, cooling heat exchange (47a , 47b, 49) can be circulated in the low-stage refrigerant circuit (9) to perform a refrigeration cycle. That is, in the heat exchanger for air conditioning (45) and the heat exchanger for cooling (47a, 47b, 49) having different utilization temperatures, different cooling media suitable for the respective utilization temperatures can be used. Therefore, it is possible to easily control the temperature of the refrigerant in each heat exchanger. [0014] The second invention is the refrigeration apparatus of the first invention, wherein the cooling heat exchanger (47a, 47b, 49) includes a refrigeration heat exchanger (47a, 47b) for cooling the inside of the refrigerator, and a freezer. And a refrigeration circuit (3,4) including the refrigeration heat exchanger (47a, 47b) in the low-stage refrigerant circuit (9). The refrigeration circuit (7) provided with the refrigeration heat exchanger (49) is connected in parallel.

[0015] In the second invention, as the cooling heat exchanger (47a, 47b, 49) provided only in the low stage side refrigerant circuit (9), the refrigeration heat exchanger (47a, 47b) for cooling the inside of the refrigerator. ) And refrigeration heat exchanger (49) that cools the inside of the freezer. Therefore, this freezing device can simultaneously perform indoor air conditioning, refrigeration in the refrigerator, and freezing in the freezer.

[0016] The third invention is the refrigeration apparatus of the second invention, wherein the refrigeration circuit (7) compresses the refrigerant sucked from the refrigeration heat exchanger (49), and the compressed refrigerant is reduced to the lower stage side. An auxiliary compressor (50) that discharges to the suction side of the low-stage compressor (39) provided in the refrigerant circuit (9) is provided!

[0017] In the third invention, the low stage side refrigerant circuit (9) is provided with the low stage side compressor (39) and the auxiliary compressor (50). In the low-stage refrigerant circuit (9), the refrigerant evaporated in the refrigeration heat exchanger (49) is compressed by the auxiliary compressor (50), and this refrigerant is further compressed by the low-stage compressor (39). The That is, a so-called two-stage compression refrigeration cycle is performed in the low-stage refrigerant circuit (9).

[0018] A fourth invention is the refrigeration apparatus of the third invention, wherein the low-stage refrigerant circuit (9) includes a suction side of the low-stage compressor (39) and the low-stage compressor (39). The first binos pipe (67) is provided to allow communication with the discharge side!

In the fourth aspect of the invention, the refrigerant on the suction side of the low stage compressor (39) is bypassed to the discharge side of the low stage compressor (39) via the first bypass pipe (67). it can. Therefore, for example, even when the low-stage compressor (39) cannot be operated due to a failure, etc., the refrigerant is circulated in the low-stage refrigerant circuit (9) by operating the auxiliary compressor (50). It can be evaporated with heat exchanger m ^ (47a, 47b, 49) for cooling.

[0020] A fifth invention is the refrigeration apparatus according to the fourth invention, wherein the low-stage refrigerant circuit (9) includes an outlet side of the refrigeration heat exchanger (47b) and an inlet side of the auxiliary compressor (50). To make it possible to communicate with With 2 bypass pipes (68)! /.

[0021] In the fifth aspect, the refrigerant on the outlet side of the refrigeration heat exchanger (47b) can be bypassed to the suction side of the auxiliary compressor (50) via the second bypass pipe (68). Therefore, for example, when the low-stage compressor (39) cannot be operated due to a failure or the like and the auxiliary compressor (50) is operated to circulate the refrigerant, the refrigerant circulated through the refrigeration heat exchanger (47b) Can be led from the second bypass pipe (68) to the suction side of the auxiliary compressor (50). Therefore, even when only the auxiliary compressor (50) is operated, the refrigerant can be circulated through the refrigeration heat exchanger (47b) to cool the refrigerator.

[0022] The sixth invention is the refrigeration apparatus of the fifth invention, wherein the downstream end force of the refrigeration heat exchanger (47b) is connected to the downstream end of the second bypass pipe (68) (refrigeration heat exchange ( The pressure adjusting mechanism (48) for adjusting the evaporation pressure of 47b) is provided.

[0023] In the sixth invention, the refrigerant on the outlet side of the refrigeration heat exchanger (47b) is auxiliary-compressed via the second bypass pipe (68) in the event of a failure of the low-stage compressor (39). The pressure adjustment mechanism (48) is installed so that the evaporating pressure of the refrigeration heat exchanger (47b) does not drop to the evaporating pressure of the refrigeration heat exchanger (49) when introduced to the suction side of the machine (50) It is done.

More specifically, for example, as described above in the fifth invention, when the low-stage compressor (39) stops due to a failure or the like, only the auxiliary compressor (50) is operated. Then, the refrigerant is circulated in the low stage side refrigerant circuit (9). Here, during the operation of the auxiliary compressor (50), the auxiliary compressor (50) is connected to the suction side of the auxiliary compressor (50) through the refrigeration heat exchanger (49) and the second bypass pipe (68). Refrigerant is circulated through the refrigeration heat exchanger (47b) connected to the suction side of the compressor (50), and each heat exchange (47b, 49) can function as an evaporator. Here, when both the heat exchangers (47b, 49) are evaporators, the refrigeration heat exchanger (47b) is larger than the refrigerant evaporation pressure in the refrigeration heat exchanger (49) due to the difference in use temperature. It is necessary to increase the evaporation pressure of the refrigerant inside. However, when the refrigeration heat exchange (47b) and the refrigeration heat exchange (49) communicate with each other via the second bypass pipe (68), the refrigerant in the refrigeration heat exchanger (47b) evaporates. The pressure may drop to the evaporation pressure of the refrigerant in the refrigeration heat exchanger (49).

[0025] In contrast, in the present invention, the downstream end force of the refrigeration heat exchanger (47b) is also the second bypass pipe (6 A pressure adjustment mechanism (48) is provided up to the downstream end of 8). Therefore, by restricting the pressure adjustment mechanism (48) to a predetermined opening, the evaporation pressure of the refrigerant in the refrigeration heat exchanger (47b) is reduced to the evaporation pressure of the refrigerant in the refrigeration heat exchanger (49). Can be avoided.

[0026] A seventh invention is the refrigeration apparatus according to any one of the third to sixth inventions, wherein the low-stage refrigerant circuit (9) includes the suction side of the auxiliary compressor (50) and the auxiliary compressor. A third bypass pipe (69) for enabling communication with the discharge side of (50) is provided! /.

In the seventh aspect, the refrigerant on the suction side of the auxiliary compressor (50) can be bypassed to the discharge side of the auxiliary compressor (50) via the third bypass pipe (69). Therefore, for example, when the auxiliary compressor (50) is stopped due to a failure or the like, the low stage side refrigerant circuit that causes the refrigerant to flow through the auxiliary compressor (50) by operating the low stage side compressor (39). It is possible to circulate within (9).

[0028] In an eighth aspect of the refrigeration apparatus according to any one of the first to seventh aspects, the low-stage side refrigerant circuit (9) has a low-stage side outdoor heat exchange that radiates heat from the refrigerant to the outdoor air. The vessel (60) is connected in series with the cascade heat exchanger (40)!

[0029] In the eighth aspect of the invention, the low-stage refrigerant circuit (9) is provided with the low-stage outdoor heat exchanger (60). Therefore, for example, when the amount of heat absorbed by the refrigerant in the heat exchanger for cooling (47a, 47b, 49) becomes larger than a predetermined amount of heat, this heat is transferred to the outside through the low-stage outdoor heat exchange (60). It can be released.

[0030] A ninth invention is the refrigeration apparatus of the eighth invention, wherein the cascade heat exchanger (40) is disposed downstream of the low-stage outdoor heat exchanger (60) in the low-stage refrigerant circuit (9). It is provided.

[0031] In the ninth aspect of the invention, the refrigerant that has radiated and condensed the low-stage outdoor heat exchanger (60) flows into the cascade heat exchanger (40). Here, in the cascade heat exchange (40), the refrigerant in the high-stage refrigerant circuit (8) recovers the heat of the refrigerant condensed in the low-stage outdoor heat exchanger (60), thereby reducing the low-stage refrigerant circuit. The refrigerant on the (9) side can be cooled. Therefore, the refrigerant on the low stage side refrigerant circuit (9) side can be supercooled.

The invention's effect

[0032] According to the first aspect, the high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are connected together. The heat exchanger for air conditioning (45) in the high-stage refrigerant circuit (8) is connected to the heat exchanger (40) through the two-stage refrigeration cycle. It can be used for heating.

[0033] Here, in the present invention, the heat exchanger for air conditioning (45) is provided only in the high stage side refrigerant circuit (8), and the heat exchanger for cooling (47a, 47b, 49) is provided in the low stage side refrigerant circuit. (9) It should be installed only. Therefore, it is possible to use different refrigerants for the air conditioning heat exchanger (45) and the cooling heat exchanger m ^ (47a, 47b, 49). For this reason, each refrigeration cycle can be performed using a refrigerant suitable for the use temperature of each heat exchanger, and temperature control in each heat exchanger can be easily performed.

[0034] According to the second invention, the refrigeration heat exchanger (47a, 47b) for cooling the inside of the refrigerator as the cooling heat exchanger (47a, 47b, 49) and the refrigeration for cooling the inside of the freezer A heat exchanger (49) is provided. Therefore, indoor air conditioning, cooling in the refrigerator, and cooling in the freezer can be performed simultaneously.

[0035] According to the third aspect of the invention, the two-stage compression refrigeration cycle is performed in the low-stage refrigerant circuit (9). Therefore, the evaporating pressure of the refrigeration heat exchanger (49) can be reliably lowered relative to the evaporating pressure of the refrigeration heat exchanger (47a, 47b), and the refrigeration heat exchanger (49) can The inside can be reliably cooled.

[0036] According to the fourth aspect of the present invention, by providing the first bypass pipe (67), the refrigerant on the suction side of the low-stage compressor (39) is supplied to the discharge side of the low-stage compressor (39). So that you can bypass it! Therefore, even when the low-stage compressor (39) fails, the refrigerant in the low-stage refrigerant circuit (9) can be circulated by operating the auxiliary compressor (50), and the heat exchange for cooling can be performed. (47b, 49) can function as an evaporator.

[0037] According to the fifth aspect, by providing the second bypass pipe (68), the refrigerant on the outlet side of the refrigeration heat exchanger (47b) can be bypassed to the suction side of the auxiliary compressor (50). I am doing so. Therefore, even when the low-stage compressor (39) fails, the auxiliary compressor (50) can be operated to circulate the refrigerant to the refrigeration heat exchanger (47b). The heat exchanger (47b) can function as an evaporator.

[0038] According to the sixth aspect of the present invention, when the low-stage compressor (39) fails, heat exchange for refrigeration is performed. When the refrigerant on the outlet side of the compressor (47b) is introduced to the suction side of the auxiliary compressor (50) via the second bypass pipe (68), the pressure adjustment mechanism (48) is squeezed to a predetermined opening to It is possible to prevent the evaporation pressure of the heat exchanger (47b) from decreasing to the evaporation pressure of the refrigeration heat exchanger (49). Therefore, even when the low-stage compressor (39) fails, the refrigerant evaporating temperature can be set different between the refrigeration heat exchanger (47b) and the refrigeration heat exchanger (49).

[0039] According to the seventh aspect of the invention, by providing the third bypass pipe (69), the refrigerant on the suction side of the auxiliary compressor (50) can be bypassed to the discharge side of the auxiliary compressor (50). And! Therefore, even when the auxiliary compressor (50) fails, the refrigerant in the low-stage refrigerant circuit (9) can be circulated by operating the low-stage compressor (39). Heat exchange m ^ (47a, 47b, 49) can function as an evaporator.

[0040] According to the eighth aspect of the invention, the low-stage side outdoor heat exchanger (60) is provided in the low-stage side refrigerant circuit (9). Therefore, when the amount of heat absorbed from the cooling heat exchange m ^ (47a, 47b, 49) is higher than the predetermined amount of heat in the lower stage refrigerant circuit (9), this heat is transferred to the lower stage outdoor heat exchanger ( 60) can be discharged to the outside. Accordingly, the cooling capacity of each cooling heat exchanger (47a, 47b, 49) can be improved.

[0041] According to the ninth aspect, the refrigerant condensed in the low-stage outdoor heat exchanger (60) is cooled with the refrigerant on the high-stage refrigerant circuit (8) side of the cascade heat exchanger (40). Thus, supercooling can be performed in the low-stage refrigerant circuit (9). Therefore, the cooling capacity of each cooling heat exchanger (47a, 47b, 49) can be further improved.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of a refrigeration apparatus according to Embodiment 1.

FIG. 2 is a schematic configuration diagram showing a refrigerant flow in a cooling operation of the refrigeration apparatus according to Embodiment 1.

FIG. 3 is a schematic configuration diagram showing a refrigerant flow in heating operation 1 of the refrigeration apparatus according to Embodiment 1.

FIG. 4 is a schematic configuration diagram showing a refrigerant flow in heating operation 2 of the refrigeration apparatus according to Embodiment 1.

FIG. 5 is a schematic diagram showing the refrigerant flow in the heating operation 3 of the refrigeration apparatus according to Embodiment 1. FIG.

FIG. 6 is a schematic configuration diagram showing a refrigerant flow when the low-stage compressor of the refrigeration apparatus according to Embodiment 1 fails.

FIG. 7 is a schematic configuration diagram of a refrigeration apparatus according to Embodiment 2.

FIG. 8 is a schematic configuration diagram showing a refrigerant flow in a cooling operation of the refrigeration apparatus according to Embodiment 2.

FIG. 9 is a schematic configuration diagram showing a refrigerant flow in heating operation 1 of the refrigeration apparatus according to Embodiment 2.

FIG. 10 is a schematic configuration diagram showing a refrigerant flow in heating operation 2 of the refrigeration apparatus according to Embodiment 2.

FIG. 11 is a schematic configuration diagram of a refrigeration apparatus according to Embodiment 3.

FIG. 12 is a schematic configuration diagram showing a refrigerant flow in a cooling operation of the refrigeration apparatus according to Embodiment 3.

FIG. 13 is a schematic configuration diagram showing a refrigerant flow in a heating operation of the refrigeration apparatus according to Embodiment 3.

Explanation of symbols

(2) Air conditioning circuit

(3,4) Refrigeration circuit

(7) Refrigeration circuit (freezer internal circuit (5), booster circuit (6))

(8) High stage refrigerant circuit

(9) Low stage refrigerant circuit

(10) Refrigeration equipment

(11) Indoor unit

(12) Air conditioning unit

(13,14) Refrigeration unit

(15) Refrigeration unit

(16) Booster unit

(31,32) High stage compressor (39) Low stage compressor

(40) Cascade heat exchanger

(45) Heat exchanger for air conditioning

(47a, 47b) Refrigeration heat exchanger

(48) Pressure regulating valve

(49) Refrigeration heat exchanger

(50) Auxiliary compressor (Booster compressor))

(67) 1st bypass piping

(68) Second bypass piping

(69) Third bypass piping

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

The refrigeration apparatus (10) according to Embodiment 1 is installed in a convenience store or the like, and performs air conditioning in the store and cooling in the showcase at the same time. This refrigeration apparatus (10) includes a high-stage refrigerant circuit (8) and a low-stage refrigerant circuit (9), and performs a two-way refrigeration cycle.

As shown in FIG. 1, the refrigeration apparatus (10) includes an outdoor unit (11), an air conditioning unit (12), first and second refrigeration units (13, 14), a refrigeration unit (15), and Has a booster unit (16). The outdoor unit (11) is installed outdoors. On the other hand, all the other units (12, 13, ...) are installed in a store such as a convenience store.

[0047] The outdoor unit (11) is provided with a high-stage outdoor circuit (la) and a low-stage outdoor circuit (lb). The air conditioning unit (12) is provided with an air conditioning circuit (2). The first and second refrigeration units (13, 14) are provided with first and second refrigeration circuits (3,4), respectively. The refrigeration unit (15) is provided with a circuit (5) in the freezer. The booster unit (16) is provided with a booster circuit (6). The freezer circuit (5) and the booster circuit (6) are connected in series to constitute a freezing circuit (7).

[0048] The refrigeration apparatus (10) includes a high-stage outdoor circuit (la) of the outdoor unit (11) and an air conditioning circuit ( 2) is connected by piping to form the above-described high-stage refrigerant circuit (8) that is a closed circuit, while the low-stage outdoor circuit (lb) of the outdoor unit (11) 2 The low-stage refrigerant circuit (9), which is a closed circuit, is configured by connecting the refrigeration circuit (3,4) and the refrigeration circuit (7) by piping. The high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are connected to each other via a cascade heat exchanger (40) described later in detail.

[0049] In the high-stage refrigerant circuit (8), the high-stage outdoor circuit (la) and the air-conditioning circuit (2) have two connection pipes (first and second connection pipes) (21, 22). Are connected to each other. The air conditioning circuit (2) is connected in series with the high-stage outdoor circuit (la).

[0050] In the low-stage refrigerant circuit (9), the low-stage outdoor circuit (lb), the first and second refrigeration circuits (3,4), and the refrigeration circuit (7) are connected in two. They are connected to each other via piping (third and fourth connecting piping) (23, 24). The refrigeration circuit (3,4) and the refrigeration circuit (7) are connected in parallel to the low-stage outdoor circuit (lb), respectively.

[0051] << Configuration of outdoor unit >>

As described above, the outdoor unit (11) is connected to the air conditioning circuit (2) to form the high stage side refrigerant circuit (8), and the first and second refrigeration units. A low-stage outdoor circuit (lb) connected to the circuit (3,4) and the refrigeration circuit (7) to form a low-stage refrigerant circuit (9). The first heat exchange section (41) of the cascade heat exchanger (40) described above is connected to the high-stage outdoor circuit (la), while the second heat exchange of the cascade heat exchanger (40) is performed. Part (42) is connected to the low-side outdoor circuit (lb).

[0052] Configuration of outdoor circuit on the high stage side

The high-stage outdoor circuit (la) consists of the first and second high-stage compressors (31, 32), the outdoor heat exchange (33), and the first and second high-stage expansion valves (34, 35 ), A high-stage receiver (36), and a first heat exchange section (41) of the cascade heat exchanger (40). The high-stage outdoor circuit (la) includes first and second four-way switching valves (37, 38) each having first to fourth ports and first to third closing valves. (51, 52, 53).

[0053] Each of the first high-stage compressor (31) and the second high-stage compressor (32) is composed of a hermetic high-pressure dome type scroll compressor. The first high-stage compressor (31) is supplied with electric power via an inverter. This first higher stage compressor (31) is connected to the output frequency of the inverter. It is composed of a so-called variable capacity compressor whose capacity can be changed by changing the rotation speed of the compressor motor by changing the number. On the other hand, the second high-stage compressor (32) is a V-type fixed capacity compressor whose compressor motor is always operated at a constant rotational speed and whose capacity cannot be changed. Talk!

[0054] One end of the first suction pipe (31a) is connected to the suction side of the first higher stage compressor (31).

On the other hand, one end of the second suction pipe (32a) is connected to the suction side of the second higher stage compressor (32).

V, ru. The other ends of the first suction pipe (31a) and the second suction pipe (32a) are connected to the main suction pipe (61). The main suction pipe (61) branches into two directions. One branch pipe of the main suction pipe (61) is connected to the first heat exchange section (41) of the cascade heat exchanger (40), and the other branch pipe is connected to the second four-way switching valve (38 ) Connect to the second port.

[0055] One end of the first discharge pipe (31b) is connected to the discharge side of the first high-stage compressor (31).

On the other hand, one end of the second discharge pipe (32b) is connected to the discharge side of the second higher stage compressor (32).

V, ru. The other ends of the first discharge pipe (31b) and the second discharge pipe (32b) are connected to the main discharge pipe (62). The second discharge pipe (32b) is provided with a first check valve (71) that allows only the flow of refrigerant from the second high-stage compressor (32) to the main discharge pipe (62). It has been. The main discharge pipe (62) branches in two directions. One branch pipe of the main discharge pipe (62) is connected to the first port of the first four-way switching valve (37), and the other branch pipe is connected to the first port of the second four-way switching valve (38). Connected to the port.

[0056] The first four-way selector valve (37) has a second port connected to the third port of the second four-way selector valve (38), and the third port is connected to the third port. 1 Connected to the first communication pipe (21) via the closing valve (51), and its fourth port is connected to one end of the outdoor heat exchanger (33) via the fifth closing valve (55). ing. The first four-way selector valve (37) has a first state (state indicated by a solid line in FIG. 1) in which the second port and the third port communicate with each other when the first port and the fourth port communicate with each other. The first port and the third port communicate with each other, and at the same time the second port and the fourth port communicate with each other, the second state (state indicated by a broken line in FIG. 1) can be switched.

[0057] The fourth port of the second four-way selector valve (38) is sealed and is not connected to the piping. The second four-way selector valve (38) has a first state (indicated by a solid 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. 1 The port can be switched to the second state (the state indicated by the broken line in FIG. 1) in which the second port and the fourth port communicate simultaneously with the third port.

The outdoor heat exchanger (33) is a cross-fin type fin-and-tube heat exchanger, and constitutes a heat source side heat exchanger in the high stage side refrigerant circuit (8). In the outdoor heat exchanger (33), heat is exchanged between the refrigerant and the outdoor air. The other end of the outdoor heat exchanger (33) is connected to both one end of the first high stage side pipe (63) and one end of the second high stage side pipe (64).

[0059] The other end of the first higher-stage pipe (63) is connected to the second connection pipe via the second check valve (72), the third check valve (73), and the second stop valve (52). Connect with (22)! On the other hand, the other end of the second high stage side pipe (64) is forced through the first high stage side expansion valve (34), the fourth check valve (74), and the second high stage side expansion valve (35). It is connected to the first heat exchange part (41) of the caded heat exchanger (40). The first and second high-stage expansion valves (34, 35) are electronic expansion valves.

[0060] The first liquid having the high-stage receiver (36) at the portion between the second check valve (72) and the third check valve (73) in the first high-stage pipe (63). One end of the tube (65) is connected. This first liquid tube

The other end of (65) is connected closer to the fourth check valve (74) in the second higher-stage pipe (64)!

. In addition, a second liquid pipe having a fifth check valve (75) is provided in a portion between the third check valve (73) and the second stop valve (52) in the first higher stage side pipe (63). One end of (66) is connected. This second liquid tube

The other end of (66) is connected to the second high stage side expansion valve (35) in the second high stage side pipe (64).

[0061] The second check valve (72) is connected to the high-stage receiver (33) from the outdoor heat exchanger (33) and the first high-stage expansion valve (34) side in the first high-stage pipe (63). Only allow refrigerant to flow to 36). The third check valve (73) in the first higher-stage pipe (63) only allows refrigerant to flow from the connection of the second liquid pipe (66) to the connection of the first liquid pipe (65). Allow. The fourth check valve (74) is configured such that in the second high-stage side pipe (64), only the flow of directional refrigerant from the connection of the first liquid pipe (65) to the first high-stage side expansion valve (34) is achieved. Is acceptable. The fifth check valve (75) is used for the second liquid pipe (66) and only the flow of the refrigerant directed to the second higher stage pipe (64) side force toward the first higher stage pipe (63). Is acceptable.

[0062] The high-stage outdoor circuit (la) includes functional parts such as various sensors, pressure switches, and filters. Is provided. Specifically, a first suction pressure sensor (81), a first suction temperature sensor (82), and a first filter (83) are provided at the junction in the main suction pipe (61). On the other hand, a first discharge temperature sensor (84) and an oil separator (85) are provided at the junction of the main discharge pipe (62). The oil separator (85) separates the refrigerating machine oil from the discharge gas cartridges of the compressors (31, 32). The refrigerating machine oil separated by the oil separator (85) is returned to the suction side of both compressors (31, 32) via an oil return pipe (not shown).

[0063] The first discharge pipe (31b) is provided with a first high pressure switch (86) and a first discharge pressure sensor (87). On the other hand, the second discharge pipe (32b) is provided with a second high-pressure switch (88). The first liquid pipe (65) is provided with a dryer filter (89). The outdoor heat exchanger (33) includes an outdoor temperature sensor (90) and an outdoor fan (91). The outdoor fan (91) blows outdoor air to the outdoor heat exchanger (33).

[0064] Configuration of low-stage outdoor circuit

The low-stage outdoor circuit (lb) includes a low-stage compressor (39), a second heat exchange section (42) of the cascade heat exchanger (40), and a low-stage receiver (43). The low-stage outdoor circuit (lb) includes fourth and fifth shut-off valves (54,55).

[0065] The low-stage compressor (39) is supplied with electric power via an inverter. This low-stage compressor (39) is a so-called variable capacity compressor whose capacity can be changed by changing the rotation speed of the compressor motor by changing the output frequency of the inverter. Yes.

[0066] The suction side of the low-stage compressor (39) is connected to the fourth connection pipe (24) via the fifth stop valve (55). On the other hand, the discharge side of the low-stage compressor (39) is connected to one end of the second heat exchange section (42) via the sixth check valve (76). The sixth check valve (76) only allows the refrigerant to flow toward the low-stage compressor (39) force second heat exchange section (42). The other end of the second heat exchange section (42) is connected to one end of the low stage receiver (43). The other end of the low-stage receiver (43) is connected to the third connecting pipe (23) via the fourth closing valve (54).

[0067] The low-stage refrigerant circuit (9) is connected to the suction side of the low-stage compressor (39) and the discharge side of the low-stage compressor (39). 1 Bypass piping (67) is provided. Specifically, one end (inflow end) of the first bypass pipe (67) is connected to the fifth shut-off valve (55) and the low-stage compressor. The other end (outflow end) of the first bypass pipe (67) is connected to the pipe between the low-stage compressor (39) and the cascade heat exchanger (40). It is connected. The first bypass pipe (67) is provided with a seventh check valve (77). The seventh check valve (77) allows only the flow of the directional refrigerant toward the outflow end of the inflow end force of the first bypass pipe (67).

[0068] As described above, the first bypass pipe (67) is used when the low-stage compressor (39) fails.

The refrigerant on the suction side of the low-stage compressor (39) is bypassed to the discharge side of the low-stage compressor (39).

[0069] The low-stage outdoor circuit (lb) is provided with various functional parts such as various sensors, pressure switches, and filters. Specifically, a second filter (92) and a second suction temperature sensor (93) are provided in a pipe between the fifth closing valve (55) and the low-stage compressor (39). In addition, the third high pressure switch (94), the second discharge temperature sensor (95), and the second discharge pressure sensor are connected to the pipe between the low-stage compressor (39) and the second heat exchanger (42). (96) is provided. Further, the first bypass pipe (67) is provided with a bypass pressure sensor (97).

[0070] <Configuration of air conditioning unit>

As described above, the air conditioning unit (12) includes the air conditioning circuit (2) that is connected to the higher-stage outdoor circuit (la) of the outdoor unit (11) and constitutes the higher-stage refrigerant circuit (8). /! The air conditioning circuit (2) includes a third filter (98), an air conditioning side expansion valve (44), and an air conditioning heat exchanger (45) in order from the connection with the second connecting pipe (22). ! / Speak.

[0071] The air conditioning side expansion valve (44) is composed of an electronic expansion valve. On the other hand, the air conditioner heat exchanger (45) is composed of a cross-fin fin “and” tube heat exchanger. In this heat exchange for air conditioning (45), heat is exchanged between the refrigerant and the room air.

[0072] Further, the air conditioning heat exchanger (45) is provided with a first air conditioning temperature sensor (99). Furthermore, in the air conditioning circuit (2), a second air conditioning temperature sensor (100) is provided in the piping between the connection portion of the first communication pipe (21) and the heat exchange for air conditioning (45). ing.

[0073] The air conditioner heat exchanger (45) is provided with an internal air temperature sensor (101) and an indoor fan (102). The indoor fan (102) blows indoor air to the heat exchanger (45) for air conditioning.

[0074] In the configuration of the air conditioning unit (12) as described above, the air conditioning heat exchanger (45) is configured to perform switching between cooling and heating in the store. [0075] <Configuration of refrigeration unit>

As described above, the refrigeration unit (13, 14) includes the lower-stage outdoor circuit (1b) and the freezing circuit (7) (freezer internal circuit (5) and booster circuit (6) of the outdoor unit (11). )) And a refrigeration circuit (3, 4) connected to the lower stage refrigerant circuit (9).

[0076] The first refrigeration circuit (3) has one end connected to the third connection pipe (23) and the other end connected to the fourth connection pipe.

(24) connected. The first refrigeration circuit (3) has a fourth filter (103), a first electromagnetic on-off valve (56a), a first filter, in order from the connection with the third communication pipe (23) (in order from the refrigerant flow direction). A first refrigeration side expansion valve (46a), a first refrigeration heat exchanger (47a), and a first refrigeration side pressure sensor (57a) are provided.

[0077] The first refrigeration side expansion valve (46a) is composed of an electronic expansion valve. The opening degree of the first refrigeration side expansion valve (46a) can be adjusted according to the pressure detected by the first refrigeration side pressure sensor (57a). On the other hand, the first refrigeration heat exchanger (47a) is composed of a cross-fin fin-and-tube heat exchanger. In the first refrigeration heat exchanger (47a), heat is exchanged between the refrigerant and the air in the refrigerator. The first refrigeration heat exchanger (47a) is provided with a first refrigerator internal temperature sensor (104) and a first refrigerator internal fan (105). The first refrigerator fan (105) blows the refrigerator air to the first refrigeration heat exchanger (47a).

[0078] One end of the second refrigeration circuit (4) is connected to a first branch pipe (25) branched from the third connection pipe (23). On the other hand, the other end of the second refrigeration circuit (4) is connected to a second branch pipe (26) branched from the fourth connection pipe (24). The second refrigeration circuit (4) includes a fifth filter (106), a second electromagnetic on-off valve (56b), a second filter in order from the connection with the first branch pipe (25) (in order from the refrigerant flow direction). 2 Refrigeration side expansion valve (46b), 2nd refrigeration heat exchanger (47b), 2nd refrigeration side pressure sensor (57b), pressure regulating valve (48) and 8th check valve (78) ).

[0079] The second refrigeration side expansion valve (46b) is composed of an electronic expansion valve. The opening of the second refrigeration side expansion valve (46b) can be adjusted according to the pressure detected by the second refrigeration side pressure sensor (57b). On the other hand, the second refrigeration heat exchanger (47b) is constituted by a cross fin type fin “and” tube type heat exchanger. In this second refrigeration heat exchanger (47b), heat is exchanged between the refrigerant and the air in the refrigerator. The second refrigeration heat exchanger (47b) The second refrigerator internal temperature sensor (107) and the second refrigerator internal fan (108) are provided. The second refrigerator fan (108) blows the refrigerator air to the second refrigeration heat exchanger (47b). In addition, the eighth check valve (78) only allows the refrigerant to flow from the second refrigeration heat exchanger (47b) to the second branch pipe (26). Further, one end of a second bypass pipe (68), which will be described in detail later, is connected to the second refrigeration circuit (4).

[0080] In the configuration of the refrigeration unit (13, 14) as described above, the refrigeration heat exchangers (47a, 47b) are configured as a heat exchanger for cooling to cool the inside of the refrigerator in the showcase. RU

[0081] <Configuration of refrigeration unit>

The refrigeration unit (15) includes the freezer internal circuit (5) as described above. The freezer internal circuit (5) has one end connected to a third branch pipe (27) further branched from the first branch pipe (25) and the other end connected to one end of the booster circuit (6). . The circuit in the freezer (5) is connected in order from the connection with the first branch pipe (25) (in order from the refrigerant flow direction), the sixth filter (109), the third electromagnetic on-off valve (56c), the freezing side expansion It has a valve (46c), a refrigeration heat exchanger (49), and a refrigeration side pressure sensor (57c).

The refrigeration side expansion valve (46c) is composed of an electronic expansion valve. The opening of the freezing side expansion valve (46c) can be adjusted according to the pressure detected by the freezing side pressure sensor (57c). On the other hand, the refrigeration heat exchanger (49) is composed of a cross-fin type fin 'and' tube heat exchanger. In the refrigeration heat exchanger (49), heat is exchanged between the refrigerant and the freezer air. The refrigeration heat exchanger (49) is provided with a freezer temperature sensor (110) and a freezer fan (111). The freezer fan (111) blows the freezer air to the freezing heat exchanger (49). The other end of a second bypass pipe (68), which will be described in detail later, is connected to the refrigeration circuit (49).

In the configuration of the refrigeration unit (15) as described above, the refrigeration heat exchanger (49) is configured as a cooling heat exchanger that cools the inside of the showcase freezer.

[0084] <Booster unit configuration>

The booster unit (16) includes the booster circuit (6) as described above. One end of this booster circuit (6) is connected to the above freezer circuit (5), and the other end is connected to the second branch pipe (26). The booster circuit (6) is connected to the freezer circuit (5) in order (cooling). A seventh filter (112), a booster compressor (auxiliary compressor) (50), and a ninth check valve (79) may be provided.

[0085] The booster compressor (50) is supplied with electric power via an inverter. The booster compressor (50) is a so-called variable capacity compressor whose capacity can be changed by changing the rotational speed of the compressor motor by changing the output frequency of the inverter. The booster compressor (50) compresses the refrigerant sucked from the in-freezer circuit (5), and discharges the compressed refrigerant to the suction side of the low-stage compressor (39) described above, thereby reducing this low pressure. The stage side compressor (39) is configured to perform so-called two-stage compression.

[0086] The ninth check valve (79) allows only the refrigerant flowing from the discharge side of the booster compressor (50) to the second branch pipe (26). Further, a fourth high pressure switch (113) is provided in the piping between the booster compressor (50) and the ninth check valve (79).

[0087] Further, the booster circuit (6) has a third bypass pipe (69) for allowing communication between the suction side of the booster compressor (50) and the discharge side of the booster compressor (50). Is provided. Specifically, one end (inflow end) of the third bypass pipe (69) is connected to the pipe between the seventh filter (112) and the booster compressor (50), and the third bypass pipe (69) The other end (outflow end) is connected to a pipe between the fourth high-pressure switch (113) and the connection of the second branch pipe (26). The third bypass pipe (69) is provided with a tenth check valve (80). The tenth check valve (80) allows only the flow of the directional refrigerant toward the outflow end as well as the inflow end force of the third bypass pipe (69).

[0088] As described above, the third binos pipe (69) allows the refrigerant on the suction side of the booster compressor (50) to be supplied to the booster compressor when the booster compressor (50) fails. (50) It is configured to make a binos on the discharge side.

[0089] <Configuration of second bypass piping>

As described above, the second bypass pipe (68) has one end connected to the second refrigeration circuit (4) and the other end connected to the freezer internal circuit (5). Specifically, one end of the second bypass pipe (68) is connected to the pipe between the pressure regulating valve (48) and the eighth check valve (78) in the second refrigeration circuit (4). It is connected. On the other hand, the other end of the second bypass pipe (68) is connected to the pipe between the freezing side pressure sensor (57c) and the booster circuit (6) in the freezer internal circuit (5). It has been continued. In this way, the second bypass pipe (68) allows communication between the outlet side of the second refrigeration heat exchanger (47b) and the suction side of the booster compressor (auxiliary compressor) (50).

[0090] The second bypass pipe (68) is provided with a bypass electromagnetic on-off valve (56d).

The bypass electromagnetic on-off valve (56d) is configured to be opened when the above-described low-stage compressor (39) fails, and closed during normal operation. Therefore, when the low-stage compressor (39) fails, by operating only the booster compressor (50), the refrigerant is circulated to the second refrigeration heat exchanger (47b) and the second refrigeration heat is The refrigerant flowing out of the refrigerant (47b) can be returned to the suction side of the booster compressor (50) via the second bypass pipe (68). Here, the pressure regulating valve (48) provided in the second refrigeration circuit (4) is configured to adjust the evaporation pressure of the second refrigeration heat exchanger (47b) to a predetermined pressure ( Details will be described later).

[0091] << Configuration of Controller >>

The refrigeration apparatus (10) of this embodiment includes a controller (200). This controller (200) adjusts the opening of each expansion valve and changes the capacity of the variable capacity compressor based on the detected values of the temperature sensor and pressure sensor. In addition, the controller (200) sets the first four-way switching valve (37) and the second four-way switching valve (38) to the state shown by the solid line in FIG. Switch to the state. Furthermore, the controller (200) opens and closes each electromagnetic on-off valve according to the operating conditions.

As described above, in the refrigeration apparatus (10) according to the present embodiment, the air conditioner heat exchanger (45) that performs switching between indoor cooling and heating is used only for the high-stage refrigerant circuit (8). On the other hand, the refrigeration heat exchanger (47a, 47b) that cools the inside of the refrigerator and the refrigeration heat exchanger (49) that cools the inside of the freezer are used as a heat exchanger for cooling, and the low-stage refrigerant circuit (9 ) Only. Here, the high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are filled with different types of refrigerant, respectively.

[0093] Driving action

Next, the operation of the refrigeration apparatus (10) according to this embodiment will be described. The refrigeration apparatus (10) is configured to perform switching between cooling operation and heating operation.

[0094] 《Cooling operation》 In the cooling operation, the inside of the store is cooled in the air conditioning unit (12), and at the same time, the air in the refrigerator is cooled in the refrigeration units (13, 14) and the refrigeration unit (15).

As shown in FIG. 2, in the high-stage refrigerant circuit (8), the first four-way switching valve (37) and the second four-way switching valve (38) are each set to the first state. Further, the first high stage side expansion valve (34) is fully closed, while the opening degrees of the second high stage side expansion valve (35) and the air conditioning side expansion valve (44) are appropriately adjusted.

[0096] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) passes through the first four-way switching valve (37 ) And flows into the outdoor heat exchanger (33). In the outdoor heat exchanger (33), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (33) passes through the high stage receiver (36) and flows through the second high stage side pipe (64). In this refrigerant, a part of the refrigerant flows through the second higher-stage pipe (64) as it is, while the remaining refrigerant is divided into the second liquid pipe (66).

[0097] The refrigerant flowing as it is through the second higher stage side pipe (64) is reduced in pressure when passing through the second higher stage side expansion valve (35), and the first heat exchange of the force cascade heat exchange (40). Flows into section (41). In the force scale heat exchanger (40), the refrigerant flowing through the first heat exchange section (41) absorbs heat from the refrigerant flowing through the second heat exchange section (42) described later and evaporates. The refrigerant evaporated in the cascade heat exchanger (40) passes through the main suction pipe (61) and is sucked into the first and second high-stage compressors (31, 32).

The refrigerant branched into the second liquid pipe (66) passes through the second communication pipe (22) and is introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) is decompressed when passing through the air conditioning side expansion valve (44), and the force also flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant absorbs heat from the room air and evaporates. Accordingly, in the air conditioning unit (12), the air cooled by the air conditioning heat exchanger (45) is supplied into the store.

[0099] The refrigerant evaporated in the heat exchanger for air conditioning (45) passes through the first connection pipe (21) and is returned to the high-stage outdoor circuit (la). The refrigerant passes through the first four-way selector valve (37), the second four-way selector valve (38), and the main suction pipe (61), and then the first and second high-stage compressors (31, 32). Inhaled.

[0100] On the other hand, in the low-stage refrigerant circuit (9), the first, second, and third electromagnetic on-off valves (56a, 56b, 56c) are opened, and the bypass electromagnetic on-off valve (56d) is closed. It becomes. Further, the opening degrees of the first and second refrigeration side expansion valves (46a, 46b) and the refrigeration side expansion valve (46c) are appropriately adjusted. [0101] When the low-stage compressor (39) and the booster compressor (50) are operated, the low-stage compressor (39) force discharged refrigerant is the second heat exchange of the cascade heat exchange (40). Flows into section (42). In the cascade heat exchanger (40), the refrigerant flowing through the second heat exchange section (42) dissipates heat to the refrigerant flowing through the first heat exchange section (41) and condenses. The refrigerant condensed in the second heat exchange section (42) of the cascade heat exchanger (40) passes through the low-stage receiver (43). Then, after passing through the third communication pipe (23), the refrigerant is divided into the first refrigeration circuit (3), the second refrigeration circuit (4), and the freezer internal circuit (5).

[0102] The refrigerant divided into the first refrigeration circuit (3) is reduced in pressure when passing through the first refrigeration side expansion valve (46a) and flows into the first refrigeration heat exchanger (47a). . In the first refrigeration heat exchanger (47a), the refrigerant absorbs heat from the air in the refrigerator and evaporates. Therefore, in the first refrigeration unit (13), the air cooled by the first refrigeration heat exchanger (47a) is supplied into the refrigerator. The refrigerant evaporated in the first refrigeration heat exchanger (47a) flows into the fourth connection pipe (24).

The refrigerant divided into the second refrigeration circuit (4) is reduced in pressure when passing through the second refrigeration side expansion valve (46b) and then flows into the second refrigeration heat exchanger (47b). In the second refrigeration heat exchanger (47b), the refrigerant absorbs heat from the air in the refrigerator and evaporates. Therefore, in the second refrigeration unit (14), the air cooled by the second refrigeration heat exchanger (47b) is supplied into the refrigerator. The refrigerant evaporated in the second refrigeration heat exchanger (47b) passes through the second branch pipe (26) and then flows into the fourth connecting pipe (24).

[0104] The refrigerant divided into the freezer circuit (5) is reduced in pressure when passing through the freezing-side expansion valve (46c) and flows into the heat freezing heat exchanger (49). In the refrigeration heat exchanger (49), the refrigerant absorbs heat from the freezer air and evaporates. Therefore, in the refrigeration unit (15), the air cooled by the freezing heat exchange (49) is supplied into the freezer. The refrigerant evaporated in the refrigeration heat exchanger (49) flows into the booster circuit (6).

[0105] The refrigerant flowing into the booster circuit (6) is sucked into the booster compressor (50) and compressed. The refrigerant compressed by the booster compressor (50) passes through the second branch pipe (26) and then flows into the fourth communication pipe (24). After circulating through the refrigeration circuit (3,4) and the refrigeration circuit (7) as described above, the refrigerant that has joined again in the fourth connection pipe (24) is transferred to the low-stage compressor (39). Inhaled. [0106] 《Heating operation》

In the heating operation, the inside of the store is heated in the air conditioning unit (12), and at the same time, the air in the refrigerator is cooled in the refrigeration units (13, 14) and the refrigeration unit (15). In this heating operation, in the cascade heat exchanger (40), the refrigerant flowing through the second heat exchange section (42) collects the heat of the refrigerant flowing through the first heat exchange section (41), so that the low stage side The heat of the refrigerant in the refrigerant circuit (9) is used for heating the heat exchanger for air conditioning (45). The refrigeration system (10) performs the following three patterns of heating operation according to the heating load in the store and the heat recovery efficiency of the cascade heat exchanger (40).

[0107] Special heating operation 1>

This operation is a heating operation in the case where the heat of the air conditioning heat exchanger (45) can be just heated using the heat recovered by the cascade heat exchanger (40). Note that the refrigerant flow in the low-stage refrigerant circuit (9) in this heating operation is the same as that in the above-described cooling operation.

As shown in FIG. 3, in the high-stage refrigerant circuit (8), the first four-way selector valve (37) is set to the second state, while the second four-way selector valve (38) Set to the first state. Further, the first high-stage side expansion valve (34) is fully closed, while the opening degree of the second high-stage side expansion valve (35) is appropriately adjusted, and the air-conditioning side expansion valve (44) is fully opened. In this heating operation 1, the refrigerant does not flow in the outdoor heat exchanger (33), and the outdoor heat exchanger (33) is stopped.

[0109] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) passes through the first four-way switching valve (37 ) And the first connecting pipe (21) and introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant dissipates heat into the room air and condenses. Therefore, in the air conditioning unit (12), the air heated by the heat exchanger for air conditioning (45) is supplied into the store.

[0110] The refrigerant condensed in the air conditioning heat exchanger (45) passes through the second connection pipe (22) and is returned to the high-stage outdoor circuit (la). The refrigerant flows into the first liquid pipe (65) from the first higher stage pipe (63) and passes through the higher stage receiver (36). Thereafter, the refrigerant is depressurized when passing through the second higher stage expansion valve (35) and flows into the first heat exchange section (41) of the power cascade heat exchange (40). In the cascade heat exchanger (40), the refrigerant flowing through the first heat exchange section (41) is transferred to the second heat exchange section. By absorbing heat from the refrigerant flowing through (42), heat is recovered from the low-stage refrigerant circuit (9) to the high-stage refrigerant circuit (8) and this refrigerant evaporates. The refrigerant that has recovered heat and evaporated in the cascade heat exchange (40) passes through the main suction pipe (61) and is sucked into the first and second high-stage compressors (31, 32).

[0111] Heating operation 2>

This operation is a heating operation performed when the heating capacity is excessive in the heating operation 1 described above. Note that the refrigerant flow in the low-stage refrigerant circuit (9) in this heating operation is the same as that in the above-described cooling operation.

As shown in FIG. 4, in the high stage side refrigerant circuit (8), the first four-way switching valve (37) and the second four-way switching valve (38) are set to the second state. Further, the first high stage side expansion valve is fully closed, while the opening degree of the second high stage side expansion valve (35) is adjusted as appropriate, and the air conditioning side expansion valve (44) is fully opened.

[0113] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) passes through the main discharge pipe (62). 1 Divides into the four-way selector valve (37) and the second four-way selector valve (38).

[0114] The refrigerant divided to the first four-way selector valve (37) side passes through the first connection pipe (21) and is introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant dissipates heat into the room air and condenses. Therefore, in the air conditioning unit (12), the air heated by the air conditioning heat exchanger (45) is supplied into the store. The refrigerant condensed in the heat exchanger for air conditioning (45) passes through the second connection pipe (22) and flows into the first high stage side pipe (63) of the high stage outdoor circuit (la).

[0115] On the other hand, the refrigerant branched to the second four-way selector valve (38) side flows into the outdoor heat exchanger (33).

In the outdoor heat exchanger (33), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (33) flows into the first higher stage side pipe (63).

[0116] The refrigerant that has joined in the first high-stage pipe (63) flows into the first liquid pipe (65), passes through the high-stage receiver (36), and passes through the second high-stage pipe (64). Circulate. This refrigerant is decompressed when passing through the second higher-stage expansion valve (35), and flows into the first heat exchange section (41) of the cascade heat exchange (40). In the cascade heat exchanger (40), the refrigerant flowing through the first heat exchanging part (41) absorbs heat from the refrigerant flowing through the second heat exchanging part (42), so that the high-stage refrigerant circuit (9) Heat recovery to the side refrigerant circuit (8) is performed and the refrigerant evaporates. The refrigerant that has recovered heat and evaporated in the cascade heat exchanger (40) passes through the main suction pipe (61) and is sucked into the first and second high-stage compressors (31, 32).

[0117] Heating operation 3>

This operation is a heating operation that is performed when the heating operation 1 has insufficient heating capacity. Note that the refrigerant flow in the low-stage refrigerant circuit (9) in the heating operation is the same as that in the above-described cooling operation.

[0118] As shown in FIG. 5, in the high-stage refrigerant circuit (8), the first four-way selector valve (37) is set to the second state, while the second four-way selector valve (38) Set to the first state. Further, the opening degrees of the first high stage side expansion valve (34) and the second high stage side expansion valve (35) are adjusted as appropriate, and the air conditioning side expansion valve (44) is fully opened.

[0119] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) passes through the first four-way switching valve (37 ) And the first connecting pipe (21) and introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant dissipates heat into the room air and condenses. Therefore, in the air conditioning unit (12), the air heated by the heat exchanger for air conditioning (45) is supplied into the store.

[0120] The refrigerant condensed in the air conditioning heat exchanger (45) passes through the second connection pipe (22) and is returned to the high-stage outdoor circuit (la). This refrigerant flows into the first liquid pipe (65) from the first higher stage pipe (63) and passes through the higher stage receiver (36). The refrigerant that has passed through the high-stage receiver (36) is divided into the cascade heat exchange (40) side and the outdoor heat exchange (33) side through the second high-stage pipe (64).

[0121] The refrigerant divided into the cascade heat exchanger (40) side is decompressed when passing through the second higher stage expansion valve (35), and the force is also reduced in the first heat exchange section (41 ). In the cascade heat exchanger (40), the refrigerant flowing through the first heat exchanging section (41) absorbs heat from the refrigerant flowing through the second heat exchanging section (42), so that the high temperature from the low stage refrigerant circuit (9). Heat recovery to the stage side refrigerant circuit (8) is performed and the refrigerant evaporates. The refrigerant that collects heat and evaporates in the cascade heat exchange (40) passes through the main suction pipe (61) and enters the first and second higher stage compressors (31, 32). Inhaled.

[0122] On the other hand, the refrigerant diverted to the outdoor heat exchanger (33) side is decompressed and flows into the outdoor heat exchanger (33) when passing through the first higher stage expansion valve (34). In the outdoor heat exchange (33), the refrigerant absorbs the outdoor aerodynamic force and evaporates. The refrigerant evaporated in the outdoor heat exchanger (33) passes through the first four-way switching valve (37), the second four-way switching valve (38), and the main suction pipe (61), and passes through the first and second high-pressure valves. It is sucked into the stage side compressor (31, 32).

[0123] Operational operation in case of failure of low stage compressor

Next, the operation when the low-stage compressor (39) fails in the low-stage refrigerant circuit (9) will be described. In this description, the flow of the refrigerant in the higher stage refrigerant circuit (8) is omitted.

[0124] As shown in FIG. 6, when the low-stage compressor (39) of the low-stage refrigerant circuit (9) fails, the first electromagnetic on-off valve (56a) is closed, The third solenoid valve (56b, 56c) and bypass solenoid valve (56d) are opened. Further, the opening degrees of the second refrigeration side expansion valves (46a, 46b), the freezing side expansion valve (46c), and the pressure regulating valve (48) are appropriately adjusted. In this operation, the refrigerant does not flow through the first refrigeration heat exchanger (47a), and the first refrigeration heat exchanger (47a) is stopped.

[0125] Here, when the booster compressor (50) is operated, the refrigerant discharged from the booster compressor (50) passes through the second branch pipe (26) and the fourth connection pipe (24). Then, it circulates on the suction side of the low stage compressor (39). Here, since the low-stage compressor (39) is in a stopped state, this refrigerant flows through the first bypass pipe (67), and then the second heat exchange section of the cascade heat exchanger (40) ( 4 Flow into 2). In the cascade heat exchanger (40), the refrigerant flowing through the second heat exchange section (42) dissipates heat to the refrigerant flowing through the first heat exchange section (41) and condenses. The refrigerant condensed in the second heat exchange section (42) of the cascade heat exchanger (40) passes through the low stage receiver (43). Then, after passing through the third connecting pipe (23), the refrigerant is divided into the second refrigeration circuit (4) and the freezer internal circuit (5).

[0126] Refrigerant that has flowed into the freezer circuit (5) is decompressed and flows into the power freezing heat exchanger (49) when passing through the freezing side expansion valve (46c). In the refrigeration heat exchanger (49), the refrigerant absorbs heat from the refrigeration air and evaporates. Therefore, in the refrigeration unit (15), heat exchange for refrigeration (49) The air cooled at is supplied into the freezer.

[0127] On the other hand, the refrigerant divided into the second refrigeration circuit (4) is reduced in pressure when passing through the second refrigeration side expansion valve (46b) and then flows into the second refrigeration heat exchanger (47b). . In the second refrigeration heat exchanger (47b), the refrigerant absorbs heat from the air in the refrigerator and evaporates. Therefore, in the second refrigeration unit (14), the air cooled by the second refrigeration heat exchanger (47b) is supplied into the refrigerator.

[0128] The refrigerant evaporated in the second refrigeration heat exchanger (47b) passes through the second bypass pipe (68) to the outlet side of the refrigeration heat exchanger (49) in the freezer circuit (5). Inflow.

[0129] By the way, when the second refrigeration heat exchanger (47b) and the refrigeration heat exchanger (49) are used as an evaporator as described above, due to the difference in the use temperature of each heat exchanger ^^, Heat exchange

9) The evaporation pressure of the refrigerant in the refrigeration heat exchanger (47b) needs to be higher than the evaporation pressure of the refrigerant inside. However, in this operation, the refrigeration heat exchanger (47b) and the refrigeration heat exchanger (49) are in communication with each other via the second bypass pipe (68). Otherwise, the evaporating pressure of the refrigerant in the refrigeration heat exchanger (47b) will drop to the evaporating pressure of the refrigerant in the refrigeration heat exchanger (49).

[0130] Therefore, during this operation, the second refrigeration heat exchange is performed by restricting the pressure adjustment mechanism (48) disposed in the vicinity of the outlet side of the second refrigeration heat exchanger (47b) to a predetermined opening. The evaporating pressure of the refrigerant in the cooler (47b) is prevented from dropping to the evaporating pressure of the refrigerant in the refrigeration heat exchanger (49).

[0131] The refrigerant combined in the freezer internal circuit (5) flows into the booster circuit (6). Then, this refrigerant is sucked into the booster compressor (50).

[0132] Effect of Embodiment 1

According to the first embodiment, the following effects are exhibited.

[0133] According to the present embodiment, the high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are connected via the cascade heat exchange (40) to perform a dual refrigeration cycle. The heat of the low-stage side refrigerant circuit (9) can be used for heating the air-conditioning heat exchanger (45) in the high-stage side refrigerant circuit (8).

[0134] In particular, according to the present invention, the heat exchanger for air conditioning (45) is provided only in the high-stage refrigerant circuit (8), and the cooling heat exchanger (47a, 47b, 49) is provided in the low-stage refrigerant circuit. (9) It should be installed only. Yo Therefore, different refrigerants can be used for the heat exchanger for air conditioning (45) and the heat exchanger for cooling (47a, 47b, 49). For this reason, each refrigeration cycle can be performed using a refrigerant suitable for the use temperature of each heat exchanger, and temperature control in each heat exchanger can be easily performed.

[0135] Also, according to the present embodiment, by providing the first bypass pipe (67), the refrigerant on the suction side of the low-stage compressor (39) is supplied to the discharge side of the low-stage compressor (39). So that you can bypass it! Therefore, even when the low-stage compressor (39) fails, the refrigerant in the low-stage refrigerant circuit (9) can be circulated by operating the booster compressor (50).

Here, a second bypass pipe (68) that can communicate with the suction side of the booster compressor (50) is provided on the outlet side of the second refrigeration heat exchanger (47b). Therefore, even when the low-stage compressor (39) fails, by operating the booster compressor (50), the refrigerant can be circulated to the second refrigeration heat exchanger (47b). Refrigeration heat exchanger (47b) can be used as an evaporator.

[0137] Further, a pressure regulating valve (48) is provided on the outlet side of the second refrigeration heat exchanger (47b).

Therefore, when the low-stage compressor (39) fails, the refrigerant on the outlet side of the second refrigeration heat exchanger (47b) is sucked into the auxiliary compressor (50) via the second bypass pipe (68). When the pressure adjustment valve (48) is throttled to the predetermined opening, the evaporation pressure of the second refrigeration heat exchanger (47b) is reduced to the evaporation pressure of the freezing heat exchanger (49). Can be avoided. Therefore, even if the low-stage compressor (39) fails, the inside of the refrigerator can be cooled to a predetermined temperature by the second refrigeration heat exchanger (47b) and the freezing heat exchanger (49). .

<< Embodiment 2 of the Invention >>

The refrigeration apparatus (10) according to Embodiment 2 is different from the refrigeration apparatus according to Embodiment 1 described above in the configuration of the refrigerant circuit. Only differences from the first embodiment will be described below.

[0139] As shown in Fig. 7, in the high-stage outdoor circuit (la) of the outdoor unit (11), only one four-way switching valve (37) is provided. The four-way selector valve (37) has its first port connected to the main discharge pipe (62), its second port connected to the main suction pipe (61), and its third port connected to the first closing valve (51 ) To the first communication pipe (21), and the fourth port is connected to the cascade heat exchanger (40). It is connected to one end of the first heat exchange part (41). The other end of the cascade heat exchange (40) is connected to one end of the outdoor heat exchange (33). The other end of the outdoor heat exchanger (33) is connected to one end of the high stage side expansion valve (34). The other end of the high stage side expansion valve (34) is connected to the second connecting pipe (22) via the second closing valve (52).

[0140] On the other hand, in the low-stage outdoor circuit (lb) of the outdoor unit (11), unlike the first embodiment, a low-stage outdoor heat exchange (60) is provided. This low-stage outdoor heat exchange (60) is connected in series with the second heat exchange section (42) of the cascade heat exchange (40)! Speak.

[0141] Specifically, one end of the low-stage outdoor heat exchanger (60) is routed through the second heat exchange section (42), the low-stage compressor (39), and the fourth shut-off valve (54). Connect to 4th connecting pipe (24)! On the other hand, the other end of the low-stage outdoor heat exchanger (60) is connected to the third connection pipe (23) via the low-stage receiver (43) and the third shut-off valve (53)! . The low-stage outdoor heat exchanger (60) is provided with a low-stage outdoor temperature sensor (114) and a low-stage outdoor fan (115). The low-stage outdoor fan (115) blows outdoor air to the low-stage outdoor heat exchanger (60). The low-stage outdoor heat exchanger (60) is configured to radiate heat from the refrigerant to the outdoor air.

[0142] As described above, the refrigeration apparatus (10) according to the second embodiment is similar to the first embodiment in that the air-conditioning heat exchanger (45) that switches between indoor cooling and heating is used as the high-stage refrigerant. On the other hand, the refrigeration heat exchanger (47a, 47b) that cools the inside of the refrigerator and the refrigeration heat exchanger (49) that cools the inside of the freezer are installed as the cooling heat exchanger. Installed only in the low-stage refrigerant circuit (9). Here, the high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are filled with different types of refrigerants.

[0143] Driving action

[0144] Cooling operation

In the cooling operation, the inside of the store is cooled in the air conditioning unit (12), and at the same time, the air in the refrigerator is cooled in the refrigeration units (13, 14) and the refrigeration unit (15).

[0145] As shown in Fig. 8, in the high stage side refrigerant circuit (8), the four-way selector valve (37) is set to the first state. In addition, while the high stage side expansion valve (34) is fully opened, the opening degree of the air conditioning side expansion valve (44) is appropriately adjusted. Adjusted.

[0146] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) passes through the four-way switching valve (37). Pass through and enter the first heat exchange section (41) of the cascade heat exchanger (40). In cascade heat exchange (40), the refrigerant flowing through the first heat exchange section (41) and the refrigerant flowing through the second heat exchange section (42) hardly exchange heat.

[0147] The refrigerant that has passed through the cascade heat exchange (40) flows into the outdoor heat exchange (33). In the outdoor heat exchanger (33), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (33) passes through the second communication pipe (22) and is introduced into the air conditioning circuit (2).

[0148] The refrigerant introduced into the air conditioning circuit (2) is decompressed and flows into the force air conditioning heat exchanger (45) when passing through the air conditioning side expansion valve (44). In the heat exchanger for air conditioning (45), the refrigerant absorbs heat from the indoor air and evaporates. Therefore, in the air conditioning unit (12), the air cooled by the heat exchange for air conditioning (45) is supplied into the store.

[0149] The refrigerant evaporated in the heat exchanger for air conditioning (45) passes through the first connection pipe (21) and is returned to the high-stage outdoor circuit (la). This refrigerant passes through the four-way selector valve (37) and the main suction pipe (61) and is sucked into the first and second high-stage compressors (31, 32).

[0150] On the other hand, when the low-stage compressor (39) and the booster compressor (50) are operated in the low-stage refrigerant circuit (9), the refrigerant is discharged from the low-stage compressor (39). The refrigerant flows into the second heat exchange section (42) of the cascade heat exchanger (40). Here, since the refrigerant temperature discharged from the low-stage compressor (39) is substantially the same as the refrigerant refrigerant discharged from the high-stage compressor (31, 32), the cascade heat exchanger (40) The refrigerant flowing through the heat exchange section (42) and the refrigerant flowing through the first heat exchange section (41) hardly exchange heat.

[0151] The refrigerant that has passed through the cascade heat exchanger (40) flows into the low-stage outdoor heat exchanger (60). In the low-stage outdoor heat exchanger (60), the refrigerant dissipates heat into the outdoor air and condenses. The refrigerant condensed in the second heat exchange section (42) passes through the low-stage receiver (43) and the third connection pipe (23), and then dissipates heat to the refrigerant flowing through the first heat exchange section (41). Condensed. The refrigerant condensed in the second heat exchange section (42) of the cascade heat exchanger (40) passes through the low-stage receiver (43) and the third connection pipe (23), and then the first refrigeration circuit (3). , Divert to the second refrigeration circuit (4) and the freezer circuit (5). The subsequent refrigerant flow in the low-stage refrigerant circuit (9) is the same as that in the first embodiment. It becomes the same as driving.

[0152] 《Heating operation》

Hereinafter, as an example of the heating operation of the refrigeration apparatus (10) of the second embodiment, the air-conditioning unit (12) performs heating in the store, and at the same time, the refrigeration unit (13, 14) and the refrigeration unit (15) Heating operation (cooling operation 1) that cools the air in the cabinet and heating in the store are performed in the air conditioning unit (12), while the refrigeration units (13, 14) and the refrigeration unit (15) are stopped. The heating operation (heating operation 2) will be described.

[0153] Heating operation 1>

As shown in FIG. 9, in the high stage side refrigerant circuit (8), the four-way selector valve (37) is set to the second state. Further, while the air conditioning side expansion valve (44) is fully opened, the opening degree of the high stage side expansion valve (34) is appropriately adjusted. In this heating operation 1, the outdoor fan (91) of the outdoor heat exchanger (33) and the low-stage outdoor fan (115) of the low-stage outdoor heat exchanger (60) are stopped.

[0154] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) flows into the four-way switching valve (37) and It passes through the first connecting pipe (21) and is introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant dissipates heat into the room air and condenses. Therefore, in the air conditioning unit (12), the air heated by the air conditioning heat exchanger (45) is supplied into the store.

[0155] The refrigerant condensed in the heat exchanger for air conditioning (45) passes through the second connection pipe (22) and is returned to the high-stage outdoor circuit (la). The refrigerant is decompressed when passing through the high-stage expansion valve (34) and then flows into the outdoor heat exchanger (33). Here, since the outdoor fan (91) of the outdoor heat exchanger (33) is stopped, the outdoor heat exchanger (33) does not actively absorb (evaporate) the refrigerant.

[0156] The refrigerant that has flowed through the outdoor heat exchanger (33) flows into the first heat exchange section (41) of the cascade heat exchanger (40). In the cascade heat exchanger (40), the refrigerant flowing through the first heat exchange section (41) absorbs heat from the refrigerant flowing through the second heat exchange section (42), so that the high-stage refrigerant circuit (9) Heat recovery to the side refrigerant circuit (8) is performed and the refrigerant evaporates. The refrigerant that has recovered heat and evaporated in the cascade heat exchanger (40) passes through the four-way selector valve (37) and the main suction pipe (61) and passes through the first and second high-stage compressors (31 , 32). [0157] On the other hand, when the low-stage compressor (39) and the booster compressor (50) are operated in the low-stage refrigerant circuit (9), the refrigerant is discharged from the low-stage compressor (39). The refrigerant flows into the second heat exchange section (42) of the cascade heat exchanger (40). In cascade heat exchange (40), the refrigerant flowing through the second heat exchange section (42) dissipates heat to the refrigerant flowing through the first heat exchange section (41) and condenses. The refrigerant that has passed through the force-scale heat exchange (40) flows into the low-stage outdoor heat exchange (60). Here, because the low-stage outdoor fan (115) of the low-stage outdoor heat exchange (60) is stopped, the low-stage outdoor heat exchanger (60) does not actively dissipate the refrigerant. Not done. The refrigerant that has passed through the second heat exchange section (42) passes through the low-stage receiver (43) and the third connection pipe (23), and then passes through the first refrigeration circuit (3) and the second refrigeration circuit ( 4) and divert to freezer circuit (5). The subsequent refrigerant flow in the low-stage refrigerant circuit (9) is the same as in the cooling operation of the first embodiment.

[0158] Heating operation 2>

As shown in FIG. 10, in the high stage side refrigerant circuit (8), the four-way selector valve (37) is set to the second state. Further, while the air conditioning side expansion valve (44) is fully opened, the opening degree of the high stage side expansion valve (34) is appropriately adjusted. In this heating operation 2, unlike the heating operation 1 of the second embodiment, the outdoor fan (91) and the low-stage outdoor fan (115) are operated. In addition, the low-stage compressor (39) and the booster compressor (50) in the low-stage refrigerant circuit (9) are stopped, and the refrigerant in the low-stage refrigerant circuit (9) does not circulate. No cooling is done! /.

[0159] When the first and second high-stage compressors (31, 32) are operated, the refrigerant discharged from both the high-stage compressors (31, 32) flows into the four-way switching valve (37) and It passes through the first connecting pipe (21) and is introduced into the air conditioning circuit (2). The refrigerant introduced into the air conditioning circuit (2) flows into the air conditioning heat exchanger (45). In the heat exchanger for air conditioning (45), the refrigerant dissipates heat into the room air and condenses. Therefore, in the air conditioning unit (12), the air heated by the air conditioning heat exchanger (45) is supplied into the store.

[0160] The refrigerant condensed in the air conditioning heat exchanger (45) passes through the second connection pipe (22) and is returned to the high-stage outdoor circuit (la). The refrigerant is decompressed when passing through the high-stage expansion valve (34) and flows into the outdoor heat exchanger (33). In outdoor heat exchange (33), the refrigerant dissipates heat to the outdoor air and condenses. The refrigerant condensed in the outdoor heat exchanger (33) flows into the first heat exchange section (41) of the cascade heat exchanger (40). Here, in the cascade heat exchanger (40), heat is exchanged between the refrigerant flowing through the first heat exchange section (41) and the refrigerant flowing through the second heat exchange section (42). Absent. The refrigerant that has passed through the cascade heat exchanger (40) passes through the four-way selector valve (37) and the main suction pipe (61) and is sucked into the first and second high-stage compressors (31, 32). .

[0161] Effect of Embodiment 2

According to the refrigeration apparatus (10) according to Embodiment 2, as in Embodiment 1, the air conditioning heat exchanger (45) is provided only in the high-stage refrigerant circuit (8), and the cooling heat exchanger (47a, 47b and 49) are provided only in the low-stage refrigerant circuit (9). Therefore, different refrigerants can be used in the air conditioning heat exchanger (45) and the cooling heat exchanger (47a, 47b, 49). For this reason, it is possible to perform each refrigeration cycle using a refrigerant suitable for the use temperature of each heat exchanger, and it is possible to easily perform temperature control in each heat exchanger.

[0162] Further, in Embodiment 2 described above, the low-stage outdoor heat exchanger (60) is provided in the low-stage refrigerant circuit (9). Therefore, in the low-stage refrigerant circuit (9), when the heat absorbed from the cooling heat exchanger m ^ (47a, 47b, 49) is higher than the predetermined heat quantity, this heat is transferred to the low-stage outdoor heat exchanger (60 ) Can be discharged outside the room. Therefore, the cooling capacity of each cooling heat exchanger (47a, 47b, 49) can be improved.

[0163] Embodiment 3 of the Invention

The refrigeration apparatus (10) according to Embodiment 3 is different from the refrigeration apparatus according to Embodiment 1 described above in the configuration of the refrigerant circuit. Only differences from the third embodiment will be described below.

[0164] As shown in FIG. 11, in the low-stage outdoor circuit (lb) of the outdoor unit (11), unlike the first embodiment, a low-stage outdoor heat exchanger (60) is provided. This low-stage outdoor heat exchanger (60) is connected in series with the second heat exchange section (42) of the cascade heat exchanger (40). Further, unlike the second embodiment, the second heat exchange section (42) of the cascade heat exchanger (40) is provided on the downstream side of the low-stage outdoor heat exchanger (60)! .

[0165] Specifically, one end of the low-stage outdoor heat exchanger (60) is connected to the fourth connection pipe (24) via the low-stage compressor (39) and the fifth shut-off valve (55). /! On the other hand, the other end of the low-stage outdoor heat exchanger (60) is connected to the third connection pipe (42) via the second heat exchange section (42), the low-stage receiver (43), and the fourth shut-off valve (54). Connect with 23)! The low-stage outdoor heat exchanger (60) is provided with a low-stage outdoor air temperature sensor (114) and a low-stage outdoor fan (115). Low-stage outdoor fan (11 In 5), outdoor air is blown to the low-stage outdoor heat exchanger (60). The low-stage outdoor heat exchanger (60) is configured to radiate heat from the refrigerant to the outdoor air.

As described above, in the refrigeration apparatus according to Embodiment 3, as in Embodiment 1, the air-conditioning heat exchanger (45) that switches between indoor cooling and heating is replaced with a high-stage refrigerant circuit (8 On the other hand, the refrigeration heat exchanger (47a, 47b) for cooling the inside of the refrigerator and the refrigerating heat exchanger (49) for cooling the inside of the freezer are used as a cooling heat exchanger. (9) Only provided. Here, the high-stage refrigerant circuit (8) and the low-stage refrigerant circuit (9) are filled with different types of refrigerant, respectively.

[0167] Driving action

Next, the operation of the refrigeration apparatus (10) according to this embodiment will be described. The refrigeration apparatus (10) is configured to perform switching between cooling operation and heating operation. Here, typical cooling operation and heating operation of the refrigeration apparatus (10) will be described.

[0168] Cooling operation

As shown in FIG. 12, the high stage side refrigerant circuit (8) performs the same operation as the cooling operation of the first embodiment.

[0169] On the other hand, in the low-stage refrigerant circuit (9), when the low-stage compressor (39) and the booster compressor (50) are operated, the low-stage compressor (39) force-discharged refrigerant Flows into the lower-stage outdoor heat exchanger (60). In the low-stage outdoor heat exchanger (60), the refrigerant dissipates heat into the outdoor air and condenses.

[0170] The refrigerant condensed in the low-stage outdoor heat exchanger (60) flows into the second heat exchange section (42) of the cascade heat exchanger (40). In the cascade heat exchanger (40), the refrigerant flowing through the second heat exchange section (42) dissipates heat to the refrigerant flowing through the first heat exchange section (41) and further condenses. That is, in the cascade heat exchange (40), the refrigerant is supercooled.

[0171] The refrigerant supercooled in the second heat exchange section (42) passes through the low-stage receiver (43) and the third connection pipe (23), and then passes through the first refrigeration circuit (3) and the second refrigeration circuit (42). 2Divert to the refrigeration circuit (4) and the freezer circuit (5). The subsequent refrigerant flow in the low-stage refrigerant circuit (9) is the same as in the cooling operation of the first embodiment.

[0172] 《Heating operation》

This operation is performed using the heat recovered by the cascade heat exchanger (40). This is a heating operation when heating can be performed exactly.

[0173] As shown in FIG. 13, in the high stage side refrigerant circuit (8), the same operation as in the heating operation 1 of the first embodiment is performed. In this heating operation, the low-stage outdoor fan (115) of the low-stage outdoor heat exchanger (60) is stopped.

[0174] In the low-stage refrigerant circuit (9), when the low-stage compressor (39) and the booster compressor (50) are operated, the refrigerant discharged by the low-stage compressor (39) is low. Pour into the outdoor heat exchange (60) on the side of the stage. Here, since the low-stage outdoor heat exchanger (115) of the low-stage outdoor heat exchange (60) is stopped, the low-stage outdoor heat exchange (60) does not actively release the refrigerant.

[0175] The refrigerant that has passed through the low-stage outdoor heat exchanger (60) flows into the second heat exchange section (42) of the cascade heat exchanger (40). In the cascade heat exchanger (40), the refrigerant flowing through the second heat exchange section (42) dissipates heat to the refrigerant flowing through the first heat exchange section (41) and condenses.

[0176] The refrigerant condensed in the second heat exchange section (42) passes through the low-stage receiver (43) and the third connection pipe (23), and then passes through the first refrigeration circuit (3) and the second refrigeration. Divide into circuit (4) and freezer circuit (5). The subsequent refrigerant flow in the low-stage refrigerant circuit (9) is the same as in the cooling operation of the first embodiment.

[0177] Effect of Embodiment 3

According to the refrigeration apparatus (10) according to Embodiment 3, as in Embodiment 1, the air conditioning heat exchanger (45) is provided only in the high-stage refrigerant circuit (8), and the cooling heat exchanger (47a, 47b and 49) are provided only in the low-stage refrigerant circuit (9). Therefore, different refrigerants can be used for the heat exchanger for air conditioning (45) and the heat exchanger for cooling (47a, 47b, 49). For this reason, it is possible to perform each refrigeration cycle using a refrigerant suitable for the use temperature of each heat exchanger, and it is possible to easily perform temperature control in each heat exchanger.

[0178] In Embodiment 3, the cascade heat exchanger (40) is provided downstream of the low-stage outdoor heat exchanger (60). Therefore, the refrigerant condensed in the low-stage outdoor heat exchange (60) is cooled by the refrigerant on the high-stage refrigerant circuit (8) side of the cascade heat exchanger (40), so that the low-stage refrigerant circuit (9) Supercooling can be performed. Therefore, the cooling capacity of each cooling heat exchanger (47a, 47b, 49) can be effectively improved.

[0179] << Other Embodiments >> The present invention may be configured as follows with respect to the above embodiment.

[0180] In Embodiment 1 described above, only the operation operation at the time of failure of the low-stage compressor (39) has been described, but when the booster compressor (50) fails, the low-stage side compressor shown in Fig. 1 By operating only the compressor (39), the refrigerant can be circulated in the low-stage refrigerant circuit (9) via the third bypass pipe (69). In this case, first, second refrigerating heat exchanger (47 _a, 47b) and can be circulated coolant to freezing heat exchanger (49) within Kakunetsu交m ^ (47a, 47b, 49) The inside of the cabinet can be cooled using as an evaporator.

[0181] Further, in the heating operation 1 of the second embodiment, the low-stage outdoor fan (115) of the low-stage outdoor heat exchanger (60) is stopped, but the heat exchange for cooling is performed. ^^ If the amount of heat absorbed from (47a, 47b, 49) is greater than a predetermined amount of heat, the low-stage outdoor fan (115) may be operated to actively dissipate heat.

[0182] Furthermore, in the heating operation of Embodiment 3 above, the heating operation in the case where heating of the air conditioning heat exchanger (45) can be performed just using the heat recovered by the cascade heat exchanger (40), However, when the heating capacity is excessive, the same operation as the heating operation 2 of the first embodiment can be performed in the high-stage refrigerant circuit (8). Further, when the heating capacity is insufficient, the same operation as the heating operation 3 of the first embodiment is performed in the high-stage refrigerant circuit (8).

Industrial applicability

[0183] As described above, the present invention is useful for a refrigeration apparatus in which a high-stage refrigerant circuit and a low-stage refrigerant circuit are connected via a cascade heat exchanger to perform a dual refrigeration cycle.

Claims

The scope of the claims

[1] A high-stage refrigerant circuit and a low-stage refrigerant circuit are connected via cascade heat exchange to perform a two-way refrigeration cycle, and an air-conditioning heat exchanger that switches between indoor cooling and heating; A refrigeration apparatus having a cooling heat exchanger for cooling the interior,

The air conditioning heat exchanger is provided only in the high-stage refrigerant circuit, while the cooling heat exchanger is provided only in the low-stage refrigerant circuit.

[2] In the refrigeration apparatus according to claim 1,

The cooling heat exchanger is composed of a refrigeration heat exchanger that cools the inside of the refrigerator, and a refrigeration heat exchanger that cools the inside of the freezer.

In the low-stage refrigerant circuit, a refrigeration apparatus comprising a refrigeration circuit including the refrigeration heat exchanger and a refrigeration circuit including the refrigeration heat exchanger connected in parallel.

[3] In the refrigeration apparatus according to claim 2,

The refrigeration circuit compresses the refrigerant sucked from the refrigeration heat exchanger, and the refrigeration circuit includes an auxiliary compressor that discharges the compressed refrigerant to the suction side of the low-stage compressor provided in the low-stage refrigerant circuit. apparatus.

[4] In the refrigeration apparatus according to claim 3,

The low-stage refrigerant circuit is a refrigeration apparatus including a first bypass pipe that enables communication between the suction side of the low-stage compressor and the discharge side of the low-stage compressor.

[5] The refrigeration apparatus according to claim 4,

The low-stage refrigerant circuit is a refrigeration apparatus including a second bypass pipe that allows communication between the outlet side of the refrigeration heat exchanger and the suction side of the auxiliary compressor.

[6] In the refrigeration apparatus according to claim 5,

A refrigeration apparatus provided with a pressure adjusting mechanism for adjusting the evaporation pressure of the refrigeration heat exchanger between the downstream end of the refrigeration heat exchanger and the downstream end of the second bypass pipe.

[7] The refrigeration apparatus according to claim 3, wherein the refrigeration apparatus according to claim 3!

The low-stage side refrigerant circuit is a refrigeration apparatus including a third bypass pipe for enabling communication between the suction side of the auxiliary compressor and the discharge side of the auxiliary compressor.

[8] In the refrigeration apparatus according to any one of claims 1 to 7,! In the low-stage refrigerant circuit, a refrigeration system in which a low-stage outdoor heat exchanger that radiates heat from the refrigerant to the outdoor air is connected in series with the cascade heat exchanger.

The refrigeration apparatus according to claim 8,

The cascade heat exchanger is a refrigeration apparatus provided on the downstream side of the low-stage outdoor heat exchanger in the low-stage refrigerant circuit.