JP2009204284A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve cooling capacity in a use-side heat exchanger of lower evaporation temperature by lowering a temperature of a refrigerant supplied to the use-side heat exchanger of lower evaporation temperature, in a refrigerating device comprising a first use-side heat exchanger and a second use-side heat exchanger having the refrigerant evaporation temperatures different from each other. <P>SOLUTION: A refrigerant circuit (4) includes a first branch passage (26) in which the refrigerant toward the first use-side heat exchanger (54) of higher evaporation temperature of the first use-side heat exchanger (54) and the second use-side heat exchanger (64) is circulated, and a second branch path (27) in which the refrigerant toward the second use-side heat exchanger (64) of lower evaporation temperature is circulated. Only the second branch path (27) of the first branch path (26) and the second branch path (27), includes an after-branching cooling means (17) for cooling the refrigerant radiating heat in a heat source-side heat exchanger (15) in a cooling operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus having cooling means for cooling a refrigerant from a radiator to an evaporator.

  2. Description of the Related Art Conventionally, a refrigeration apparatus having a cooling means for cooling a refrigerant from a radiator to an evaporator is known. In this type of refrigeration apparatus, a cooling means is used to improve the cooling capacity of the use side heat exchanger.

Patent Document 1 discloses a refrigeration apparatus in which two internal heat exchangers are connected in parallel to a refrigerant circuit. In this refrigeration apparatus, a supercooling heat exchanger is provided as a cooling means in a pipe through which the refrigerant flows from the external heat exchanger serving as a radiator (condenser) during the cooling operation toward the internal heat exchanger. ing. In the supercooling heat exchanger, the refrigerant heading to each internal heat exchanger is cooled by the refrigerant reduced to the intermediate pressure by the first external expansion valve.
JP 2007-178052 A

  By the way, in the conventional refrigeration apparatus, the refrigerant radiated by the heat source side heat exchanger is distributed to each use side heat exchanger after being cooled by the cooling means. For this reason, the temperature of the refrigerant | coolant supplied to each utilization side heat exchanger becomes substantially equal. However, in the configuration of the conventional refrigeration apparatus, when the evaporation temperatures of the refrigerants in the two usage-side heat exchangers are set to different values (for example, one usage-side heat exchanger is used for indoor air conditioning and the other When the use side heat exchanger is used for cooling the inside of the cabinet), there is a problem that a refrigerant having a sufficiently low temperature cannot be supplied to the use side heat exchanger having the lower evaporation temperature. This will be described below.

  In the decompression process of the refrigeration cycle, the temperature of the refrigerant before being reduced to the low pressure of the refrigeration cycle is higher than the temperature of the refrigerant after being reduced to the low pressure of the refrigeration cycle. That is, the temperature of the refrigerant after being cooled by the cooling means becomes higher than the evaporation temperature of the refrigerant in the use side heat exchanger. For this reason, in the configuration of the conventional refrigeration apparatus in which the temperature of the refrigerant supplied to each usage-side heat exchanger is approximately equal, the temperature of the refrigerant supplied to both usage-side heat exchangers (that is, cooled by the cooling means) The temperature of the later refrigerant) is restricted by the evaporation temperature of the refrigerant in the use side heat exchanger with the higher evaporation temperature. Therefore, the refrigerant cannot be cooled to a sufficiently low temperature with respect to the use side heat exchanger having the lower evaporation temperature.

  This invention is made | formed in view of this point, The objective is an evaporating temperature in a freezing apparatus provided with the 1st utilization side heat exchanger and 2nd utilization side heat exchanger from which the evaporating temperature of a refrigerant | coolant differs mutually. The purpose is to reduce the temperature of the refrigerant supplied to the lower use side heat exchanger and to improve the cooling capacity of the lower use side heat exchanger whose evaporation temperature is lower.

  The first invention is provided with a compression mechanism (40), a heat source side heat exchanger (15), a first usage side heat exchanger (54), and a second usage side heat exchanger (64), and the refrigerant is supplied. A refrigerant circuit (4) that circulates to perform a refrigeration cycle is provided, and in the refrigerant circuit (4), the heat source side heat exchanger (15) operates as a radiator and the first use side heat exchanger (54). And the second usage-side heat exchanger (64) performs a cooling operation that operates as an evaporator, and in the cooling operation, the evaporation temperature of the refrigerant in the second usage-side heat exchanger (64) is the first usage. A refrigeration apparatus set to a temperature lower than the evaporation temperature of the refrigerant in the side heat exchanger (54) is a target.

  In the refrigeration apparatus, the refrigerant flowing from the heat source side heat exchanger (15) to the first usage side heat exchanger (54) and the second usage side heat exchanger (64) is supplied during the cooling operation. The main liquid side passage (24, 25) that circulates and the refrigerant that branches from the main liquid side passage (24, 25) and travels toward the first use side heat exchanger (54) during the cooling operation. A first branch passage (26) and a second branch passage through which refrigerant flows from the main liquid side passages (24, 25) to the second use side heat exchanger (64) during the cooling operation. (27), and only the second branch passage (27) of the first branch passage (26) and the second branch passage (27) is provided with the heat source side heat exchanger (15) during the cooling operation. ) Is provided with a post-branch cooling means (17) for cooling the refrigerant that has dissipated the heat in

  In the first invention, during the cooling operation, the refrigerant radiated by the heat source side heat exchanger (15) flows from the main liquid side passages (24, 25) to the first branch passage (26) and the second branch passage (27). Branch to In the first invention, the post-branch cooling means (17) is provided only in the second branch passage (27) of the first branch passage (26) and the second branch passage (27). For this reason, the refrigerant supplied to the first usage side heat exchanger (54) is not cooled in the first branch passage (26). The second usage-side heat exchanger (64) is supplied with the refrigerant cooled by the after-branch cooling means (17). Accordingly, the refrigerant supplied to the second usage side heat exchanger (64) has a lower temperature than the refrigerant supplied to the first usage side heat exchanger (54). In this 1st invention, it supplies to the 2nd utilization side heat exchanger (64) with a lower evaporation temperature among a 1st utilization side heat exchanger (54) and a 2nd utilization side heat exchanger (64). Since the post-branch cooling means (17) for cooling only the refrigerant is provided, the post-branch cooling means (17) regardless of the refrigerant evaporation temperature in the first use side heat exchanger (54) having the higher evaporation temperature. As a result, the refrigerant supplied to the second usage-side heat exchanger (64) is cooled.

  According to a second aspect of the present invention, in the first aspect, the main liquid side passages (24, 25) are arranged before the branch for cooling the refrigerant radiated by the heat source side heat exchanger (15) during the cooling operation. Cooling means (18) is provided.

  In the second aspect of the present invention, the refrigerant radiated by the heat source side heat exchanger (15) during the cooling operation is cooled by the pre-branch cooling means (18) and then the first branch passage (26) and the second branch passage. Branch to (27). For this reason, the refrigerant cooled by the pre-branch cooling means (18) is supplied to the first usage-side heat exchanger (54).

  According to a third aspect, in the second aspect, the post-branch cooling means (17) is lower than the high-temperature side passage through which the refrigerant in the second branch passage (27) flows and the refrigerant in the high-temperature side passage The low-temperature side passage through which the temperature refrigerant flows is constituted by a first cooling heat exchanger (17) that exchanges heat, and the pre-branch cooling means (18) is a refrigerant in the main liquid side passage (24, 25). While the high temperature side passage through which the refrigerant flows and the low temperature side passage through which the refrigerant having a temperature lower than that of the refrigerant in the high temperature side passage is configured by the second cooling heat exchanger (18), In the cooling heat exchanger (17) and the second cooling heat exchanger (18), the first cooling heat exchanger (17) has a lower temperature refrigerant flowing through the low temperature side passage.

  In 3rd invention, the refrigerant | coolant supplied to a 2nd utilization side heat exchanger (64) distribute | circulates in order of a 2nd cooling heat exchanger (18) and a 1st cooling heat exchanger (17). The refrigerant supplied to the second usage side heat exchanger (64) is cooled by the refrigerant in the low temperature side circuit of the second cooling heat exchanger (18), and then the low temperature side of the first cooling heat exchanger (17). Cooled by the refrigerant in the circuit. The temperature of the refrigerant in the low temperature side circuit of the first cooling heat exchanger (17) is lower than the temperature of the refrigerant in the low temperature side circuit of the second cooling heat exchanger (18). In this 3rd invention, in this 3rd invention, the refrigerant | coolant supplied to a 2nd utilization side heat exchanger (64) performs heat exchange in an order from a refrigerant | coolant with a higher temperature.

  In a fourth aspect based on the third aspect, the compression mechanism (40) includes a high-temperature compressor (14b, 14c) that sucks the refrigerant evaporated in the first usage-side heat exchanger (54). And a low-temperature compressor (14a, 14b) for sucking the refrigerant evaporated in the second usage side heat exchanger (64), while a compression chamber for intermediate pressure of the high-temperature compressor (14b, 14c) A first decompression means (66) provided in a first injection passage (28) for injecting the refrigerant into (73) and decompressing the refrigerant flowing through the first injection passage (28); Provided in the second injection passage (29) for injecting the refrigerant into the intermediate pressure compression chamber (73) of the machine (14a, 14b), and the refrigerant flowing through the second injection passage (29) Second decompression means (67) for decompressing to a pressure lower than that of the refrigerant decompressed by the decompression means (66), The low temperature side passage of the first cooling heat exchanger (17) is disposed downstream of the second decompression means (67) in the second injection passage (29), and the low temperature of the second cooling heat exchanger (18). A side passage is disposed downstream of the first pressure reducing means (66) in the first injection passage (28).

  In the fourth aspect of the invention, the high temperature compressor (14b, 14c) is the first usage side with the higher evaporation temperature of the first usage side heat exchanger (54) and the second usage side heat exchanger (64). The refrigerant that has evaporated in the heat exchanger (54) is sucked in, and the low-temperature compressors (14a, 14b) suck in the refrigerant that has evaporated in the second usage-side heat exchanger (64) having the lower evaporation temperature. And the refrigerant | coolant decompressed by the 1st pressure reduction means (66) is inject | poured into the compression chamber (73) of the intermediate pressure of the compressor (14b, 14c) for high temperature through the 1st injection channel (28), and compression for low temperature The refrigerant decompressed by the second decompression means (67) is injected through the second injection passage (29) into the intermediate pressure compression chamber (73) of the machine (14a, 14b). In the second decompression means (67), the refrigerant is decompressed to a pressure lower than that of the refrigerant decompressed by the first decompression means (66). For this reason, refrigerant having a low evaporation temperature is sucked into the intermediate pressure compression chamber (73) of the high temperature compressor (14b, 14c) and the intermediate pressure compression chamber (73) of the low temperature compressor (14a, 14b). A refrigerant having a low pressure is injected into the low-temperature compressor (14a, 14b). In the fourth aspect of the invention, the temperature of the refrigerant downstream of the second pressure reducing means (67) is lower than that of the refrigerant downstream of the first pressure reducing means (66). The low temperature side passage of the first cooling heat exchanger (17) is disposed downstream of the second decompression means (67), and the low temperature side passage of the second cooling heat exchanger (18) through which the higher temperature refrigerant flows is 1 Disposed downstream of the decompression means (66). In the present specification, the intermediate pressure compression chamber (73) is a compression chamber (73) communicating with each injection passage (28, 29). In the intermediate pressure compression chamber (73), there is refrigerant in the middle of the compression stroke.

  In the present invention, only the refrigerant supplied to the second usage side heat exchanger (64) having the lower evaporation temperature out of the first usage side heat exchanger (54) and the second usage side heat exchanger (64) is used. Since the post-branch cooling means (17) for cooling is provided, the second post-branch cooling means (17) uses the second post-branch cooling means (17) regardless of the refrigerant evaporation temperature in the first use side heat exchanger (54) having the higher evaporation temperature. The refrigerant supplied to the use side heat exchanger (64) is cooled. For this reason, compared with the conventional structure in which the temperature of the refrigerant | coolant supplied to a 1st user-side heat exchanger (54) and the temperature of the refrigerant | coolant supplied to a 2nd user-side heat exchanger (64) become substantially equal, The temperature of the refrigerant supplied to the second usage side heat exchanger (64) can be lowered. Therefore, the cooling capacity in the second usage side heat exchanger (64) can be improved, and the operating efficiency of the refrigeration apparatus can be improved.

  Moreover, if the temperature of the refrigerant | coolant supplied to a 2nd usage-side heat exchanger (64) is reduced, the density of the refrigerant | coolant supplied to a 2nd usage-side heat exchanger (64) will become high (volumetric flow volume will reduce). ). Therefore, the pressure loss when the refrigerant supplied to the second usage-side heat exchanger (64) is depressurized can be reduced, and this can also improve the operating efficiency of the refrigeration apparatus.

  In the second aspect of the invention, the pre-branch cooling means (18) is provided in the main liquid side passage (24, 25), so that the first use-side heat exchanger (54) is provided with the pre-branch cooling means (18). A cooled refrigerant is supplied. For this reason, since the temperature of the refrigerant | coolant supplied to a 1st utilization side heat exchanger (54) can be reduced compared with the case where a pre-branch cooling means (18) is not provided, a 1st utilization side heat exchanger ( The cooling capacity in 54) can be improved, and the operating efficiency of the refrigeration apparatus can be improved.

  Moreover, in the said 3rd invention, the refrigerant | coolant supplied to a 2nd utilization side heat exchanger (64) is the refrigerant | coolant of the low temperature side circuit of a 1st cooling heat exchanger (17), and a 2nd cooling heat exchanger (18). ) Heat exchange is performed in order from the refrigerant having the higher temperature among the refrigerants in the low temperature side circuit. Therefore, in both the first cooling heat exchanger (17) and the second cooling heat exchanger (18), the refrigerant on the cooled side supplied to the second usage side heat exchanger (64) and the low temperature side A relatively large temperature difference can be ensured between the refrigerant on the cooling side of the circuit. Therefore, since the heat exchange efficiency in the whole of the first cooling heat exchanger (17) and the second cooling heat exchanger (18) is improved, the temperature of the refrigerant supplied to the second usage side heat exchanger (64) is reduced. Further, the cooling capacity in the second usage side heat exchanger (64) can be further increased.

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

  This embodiment is a refrigeration apparatus (1) according to the present invention. The refrigeration apparatus (1) is provided in a convenience store, for example. As shown in FIG. 1, the refrigeration apparatus (1) includes an outdoor unit (10) installed outside the room, an indoor unit (50) that air-conditions the store space, and two internal units that cool the interior. (60a, 60b) and a booster unit (80). The two internal units (60a, 60b) are composed of a refrigeration unit (60a) and a refrigeration unit (60b).

  The external unit (10) has an external circuit (11), the indoor unit (50) has an indoor circuit (52), the refrigeration unit (60a) has a first internal circuit (61a), a refrigeration unit ( The second internal circuit (61b) is provided in 60b), and the booster circuit (81) is provided in the booster unit (80). In this refrigeration system (1), the external circuit (11), the indoor circuit (52), the first internal circuit (61a), the second internal circuit (61b), and the booster circuit (81) are connected in four ways. A refrigerant circuit (4) that performs a vapor compression refrigeration cycle is configured by connecting the pipes (2a, 2b, 3a, 3b). The first internal circuit (61a) and the second internal circuit (61b) are connected in parallel. The second internal circuit (61b) and the booster circuit (81) are connected in series.

  The four connecting pipes (2a, 2b, 3a, 3b) are the first liquid side connecting pipe (2a), the second liquid side connecting pipe (2b), the first gas side connecting pipe (3a), and the second gas. Consists of side connecting piping (3b). One end of the first liquid side connecting pipe (2a) is connected to the first liquid side closing valve (111) of the external circuit (11), and the other end is connected to the indoor circuit (52). One end of the second liquid side connecting pipe (2b) is connected to the second liquid side shut-off valve (112) of the external circuit (11), and the other end branches into two hands, and the first internal circuit (61a) And the second internal circuit (61b). One end of the first gas side communication pipe (3a) is connected to the first gas side closing valve (113) of the external circuit (11), and the other end is connected to the indoor circuit (52). One end of the second gas side connecting pipe (3b) is connected to the second gas side shut-off valve (114) of the external circuit (11), and the other end branches into two hands, and the first internal circuit (61a) And the second internal circuit (61b). The second internal circuit (61b) and the booster circuit (81) are connected by a connection gas pipe (5).

《Outside unit》
The external circuit (11) is provided with a compression mechanism (40), an external heat exchanger (15), and a receiver (16). The compression mechanism (40) includes a first compressor (14a) having a variable operating capacity, a second compressor (14b) having a fixed operating capacity, and a third compressor (14c) having a fixed operating capacity. Has been. These compressors (14a, 14b, 14c) are connected in parallel to each other. In addition, the 3rd compressor (14c) may be comprised by the compressor with a variable operating capacity.

  The first compressor (14a) constitutes an in-compartment compressor (low temperature compressor) that sucks the refrigerant evaporated in the in-compartment units (60a, 60b). The first compressor (14a) is a compressor dedicated to the interior. The third compressor (14c) constitutes an indoor compressor (high temperature compressor) that sucks the refrigerant evaporated in the indoor unit (50) during the cooling operation. The third compressor (14c) is a compressor dedicated to the room. The second compressor (14b) constitutes an internal compressor when a later-described third four-way switching valve (33) is in the first state, and the third four-way switching valve (33) The in-compartment compressor is configured in the two state. That is, the second compressor (14b) constitutes a combined compressor that is used as both the internal compressor and the internal compressor.

  The first compressor (14a), the second compressor (14b), and the third compressor (14c) are all configured as, for example, a fully sealed high-pressure dome type scroll compressor. Electric power is supplied to the first compressor (14a) via an inverter. The first compressor (14a) is configured such that its operating capacity can be adjusted in stages by changing the output frequency of the inverter. On the other hand, in the second compressor (14b) and the third compressor (14c), the electric motor is always operated at a constant rotational speed, and the operation capacity cannot be changed. Details of the configuration of the compressor (14) will be described later.

  The first discharge pipe (56a) of the first compressor (14a), the second discharge pipe (56b) of the second compressor (14b), and the third discharge pipe (56c) of the third compressor (14c) are 1 It is connected to the discharge junction pipe (21). The discharge junction pipe (21) is connected to the first four-way switching valve (31). A discharge branch pipe (97) branches off from the discharge junction pipe (21). The discharge branch pipe (97) is connected to the second four-way switching valve (32).

  Each discharge pipe (56) has an oil separator (37a, 37b, 37c), high pressure switch (39a, 39b, 39c) and check valve (CV1, CV2, CV3) in order from the compressor (14) side. And are arranged. Each high pressure switch (39) is configured to urgently stop the compressor (14) when the pressure is abnormally high. Each check valve (CV1, CV2, CV3) is configured to prohibit the flow of refrigerant toward the compressor (14).

  Each oil separator (37) is configured in a closed container shape, and is configured to separate the refrigeration oil from the refrigerant discharged from the compressor (14). In this embodiment, the oil separator (37) is provided in each discharge pipe (56), so that the oil separator (37) is smaller than the case where one oil separator is provided in the discharge junction pipe (21). It is planned.

  Each oil separator (37a, 37b, 37c) is provided with an oil return pipe (38a, 38b, 38c). Each oil return pipe (38a, 38b, 38c) connects an oil separator (37a, 37b, 37c) to an injection pipe (28-30) described later. Each oil return pipe (38) has a check valve (CV4, CV5, CV6) that prohibits the flow of refrigerant from the oil separator (37) side to the oil separator (37) and a high-pressure refrigerant in the middle. Capillary tubes (41a, 41b, 41c) that are depressurized to a pressure are provided. A capillary tube (41a) of the first oil return pipe (38a) for returning the refrigeration oil to the first compressor (14a) and a second oil return for returning the refrigeration oil to the second compressor (14b). The capillary tube (41b) of the pipe (38b) is longer than the capillary tube (41c) of the third oil return pipe (38c) for returning the refrigeration oil to the third compressor (14c). . Also, each oil separator (37a, 37b, 37c) has oil between the check valve (CV4, CV5, CV6) and the capillary tube (41a, 41b, 41c) while the compressor (14) is stopped. A liquid seal prevention pipe (22a, 22b, 22c) for preventing the separator (37) from entering a liquid seal state is connected.

  The first suction pipe (57a) of the first compressor (14a) is connected to the second gas side shut-off valve (114). The second suction pipe (57b) of the second compressor (14b) is connected to the third four-way switching valve (33). The third suction pipe (57c) of the third compressor (14c) is connected to the second four-way switching valve (32). A first suction branch pipe (58a) branches off from the first suction pipe (57a). A second suction branch pipe (58b) branches off from the third suction pipe (57c). Both the first suction branch pipe (58a) and the second suction branch pipe (58b) are connected to the third four-way switching valve (33). The first suction branch pipe (58a) and the second suction branch pipe (58b) have check valves (CV7, CV8) for prohibiting the flow of refrigerant from the third four-way switching valve (33) side, respectively. Is provided.

  The external heat exchanger (15) is a cross-fin type fin-and-tube heat exchanger. The external heat exchanger (15) constitutes a heat source side heat exchanger. In the vicinity of the external heat exchanger (15), an external fan (23) that sends external air to the external heat exchanger (15) is provided. In the external heat exchanger (15), heat is exchanged between the refrigerant and the external air.

  The gas side of the external heat exchanger (15) is connected to the first four-way switching valve (31). The liquid side of the external heat exchanger (15) is connected to the top of the receiver (16) via the first liquid pipe (24). The first liquid pipe (24) is provided with a check valve (CV9) that prohibits the flow of refrigerant toward the external heat exchanger (15). The first liquid pipe (24) is provided with a check valve (CV10) that prohibits the flow of refrigerant toward the receiver (16) in parallel with the check valve (CV9).

  The receiver (16) is configured in a vertically long sealed container shape. In the receiver (16), the high-pressure refrigerant condensed in the external heat exchanger (15) or the like is temporarily stored. In addition to the first liquid pipe (24), a gas vent pipe (48) provided with an openable / closable fourth electromagnetic valve (SV4) is connected to the top of the receiver (16). One end of the second liquid pipe (25) is connected to the bottom of the receiver (16).

  The second liquid pipe (25), together with the first liquid pipe (24), during the cooling operation to be described later, from the external heat exchanger (15) to the indoor heat exchanger (54) and the internal heat exchanger (64) The main liquid side passages (24, 25) through which the refrigerant flowing toward the refrigerant flow are configured. The second liquid pipe (25) is provided with a second cooling heat exchanger (18) constituting the pre-branch cooling means. In the second cooling heat exchanger (18), the refrigerant condensed in the external heat exchanger (15) during the cooling operation is cooled. The other end of the second liquid pipe (25) branches into a first branch pipe (26) and a second branch pipe (27).

  The first branch pipe (26) is connected to the first liquid side stop valve (111). The first branch pipe (26) communicates with the indoor heat exchanger (54) through the first liquid side communication pipe (2a), and branches from the main liquid side passage (24, 25) during the cooling operation. A first branch passage (26) through which the refrigerant toward the indoor heat exchanger (54) flows is configured. The first branch pipe (26) is provided with a check valve (CV16) that prohibits the flow of refrigerant toward the second liquid pipe (25). A third branch pipe (47) connected between the check valve (CV9) and the receiver (16) in the first liquid pipe (24) branches from the first branch pipe (26). The third branch pipe (47) is provided with a check valve (CV11) that prohibits the flow of refrigerant toward the first liquid side stop valve (111).

  The second branch pipe (27) is connected to the second liquid side stop valve (112). The second branch pipe (27) communicates with the internal heat exchanger (64) through the second liquid side connecting pipe (2b) and branches from the main liquid side passage (24, 25) during the cooling operation. Thus, a second branch passage (27) through which the refrigerant directed to each internal heat exchanger (64) flows is configured. The second cooling pipe (27) is provided with the first cooling heat exchanger (17). The second branch pipe (27) is provided in series with the second cooling heat exchanger (18). Further, a bypass pipe (51) and a connection injection pipe (9) are branched from the second branch pipe (27).

  In the present embodiment, the refrigerant path constituted by the first liquid pipe (24), the second liquid pipe (25), the first branch pipe (26), and the second branch pipe (27) is a liquid side path ( 20). In the liquid side passage (20), only the second branch pipe (27) of the first branch pipe (26) and the second branch pipe (27) has a cooling heat exchanger (18) that constitutes a post-branching cooling means. Is provided.

  The bypass pipe (51) branches off from between the second cooling heat exchanger (18) and the second liquid side shut-off valve (112). The bypass pipe (51) has the opposite end to the one connected to the second branch pipe (27) between the external heat exchanger (15) and the check valve (CV9) in the first liquid pipe (24). It is connected to the. The bypass pipe (51) is provided with a third outside expansion valve (65) constituted by an electronic expansion valve having a variable opening.

  The connection injection pipe (9) is branched from between the branch point of the bypass pipe (51) and the second liquid side shut-off valve (112). The connection injection pipe (9) branches into the first injection pipe (28) and the second injection pipe (29) at the end opposite to the side connected to the second branch pipe (27).

  The first injection pipe (28) is connected to the intermediate pressure compression chamber (73) of the third compressor (14c) at the opposite end to the one connected to the connection injection pipe (9). The first injection pipe (28) constitutes a first injection passage (28) that communicates with the intermediate pressure compression chamber (73) of the indoor compressor (14b, 14c). The first injection pipe (28) is provided with a second cooling heat exchanger (18). Further, the first injection pipe (28) is provided with a first outside expansion valve (66) constituted by an electronic expansion valve having a variable opening degree and a third electromagnetic valve (SV3) which can be opened and closed.

  The first external expansion valve (66) constitutes a first pressure reducing means (66) for reducing the pressure of the refrigerant injected into the intermediate pressure compression chamber (73) of the indoor compressor (14b, 14c). The first external expansion valve (66) is provided upstream of the second cooling heat exchanger (18). The third solenoid valve (SV3) is provided between the second cooling heat exchanger (18) and the third compressor (14c). The third solenoid valve (SV3) is set to a closed state while the third compressor (14c) is stopped.

  On the other hand, the second injection pipe (29) is connected to the intermediate pressure compression chamber (73) of the first compressor (14a) at the opposite end to the one connected to the connection injection pipe (9). The second injection pipe (29) constitutes a second injection passage (29) communicating with the intermediate pressure compression chamber (73) of the internal compressor (14a, 14b). The second injection pipe (29) is provided with a first cooling heat exchanger (17). The second injection pipe (29) is provided with a second external expansion valve (67) constituted by an electronic expansion valve having a variable opening degree and a first electromagnetic valve (SV1) that can be freely opened and closed. .

  The second external expansion valve (67) is provided upstream of the first cooling heat exchanger (17). The second external expansion valve (67) constitutes a second pressure reducing means (67) for reducing the pressure of the refrigerant injected into the intermediate pressure compression chamber (73) of the internal compressor (14a, 14b). . On the other hand, the first solenoid valve (SV1) is provided between the first cooling heat exchanger (17) and the first compressor (14a). The first solenoid valve (SV1) is set to a closed state while the first compressor (14a) is stopped. Further, the degassing pipe (48) is connected to the first injection pipe (28) at a position between the first cooling heat exchanger (17) and the first electromagnetic valve (SV1).

  In addition, the first injection branch pipe (49a) branches from the first injection pipe (28) between the second cooling heat exchanger (18) and the third electromagnetic valve (SV3). A second injection branch pipe (49b) branches from the second injection pipe (29) between the first cooling heat exchanger (17) and the first electromagnetic valve (SV1). Each injection branch pipe (49a, 49b) is connected to the fourth four-way selector valve (34). Each injection branch pipe (49a, 49b) is provided with a check valve (CV12, CV13) for prohibiting the flow from the fourth four-way selector valve (34) side.

  Connected to the fourth four-way selector valve (34) is a third injection pipe (30) connected to the intermediate pressure compression chamber (73) of the second compressor (14b). The third injection pipe (30) is provided with a second electromagnetic valve (SV2) that can be freely opened and closed. The second solenoid valve (SV2) is set to a closed state while the second compressor (14b) is stopped. The 3rd injection pipe (30) constitutes the injection passage (28-30) with the 1st injection pipe (28) and the 2nd injection pipe (29).

  Moreover, each oil return pipe | tube (38) is connected to each injection pipe | tube (28-30) as mentioned above. In this embodiment, when the refrigeration oil in the oil separator (37) is returned to the suction side of the compressor (14), the refrigerant flow rate that the compressor (14) sucks from the suction side is reduced by the amount of the refrigeration oil. The structure which returns the refrigeration oil of an oil separator (37) to the compression chamber (73) of intermediate pressure is employ | adopted.

  The first cooling heat exchanger (17) is provided to straddle the second injection pipe (29) and the second branch pipe (27). The first cooling heat exchanger (17) includes a high temperature side passage (17a) through which the refrigerant in the second branch pipe (27) flows, and a low temperature side passage (17b) through which the refrigerant in the second injection pipe (29) flows. It has. The first cooling heat exchanger (17) is configured to exchange heat between the refrigerant flowing through the high temperature side passage (17a) and the refrigerant flowing through the low temperature side passage (17b). The first cooling heat exchanger (17) is constituted by, for example, a plate heat exchanger.

  The low temperature side passage (17b) of the first cooling heat exchanger (17) is disposed downstream of the second external expansion valve (67) in the second injection pipe (29). The refrigerant decompressed by the second external expansion valve (67) flows into the low temperature side passage (17b). In the first cooling heat exchanger (17), the high pressure refrigerant flowing through the high temperature side passage (17a) is cooled by the intermediate pressure refrigerant flowing through the low temperature side passage (17b). In the first cooling heat exchanger (17), the refrigerant supplied to each internal heat exchanger (64) is cooled by the intermediate-pressure refrigerant decompressed by the second external expansion valve (67).

  The second cooling heat exchanger (18) is provided to straddle the first injection pipe (28) and the second liquid pipe (25). The second cooling heat exchanger (18) includes a high temperature side passage (18a) through which the refrigerant in the second liquid pipe (25) flows, and a low temperature side passage (18b) through which the refrigerant in the first injection pipe (28) flows. It has. The second cooling heat exchanger (18) is configured to exchange heat between the refrigerant flowing through the high temperature side passage (18a) and the refrigerant flowing through the low temperature side passage (18b). The second cooling heat exchanger (18) is constituted by, for example, a double tube heat exchanger.

  The low temperature side passage (18b) of the second cooling heat exchanger (18) is disposed downstream of the first external expansion valve (66) in the first injection pipe (28). The refrigerant depressurized by the first external expansion valve (66) flows into the low temperature side passage (18b). In the second cooling heat exchanger (18), the high-pressure refrigerant flowing through the high temperature side passage (18a) is cooled by the intermediate pressure refrigerant flowing through the low temperature side passage (18b). In the second cooling heat exchanger (18), the refrigerant supplied to the indoor heat exchanger (54) and the internal heat exchanger (64) is an intermediate pressure refrigerant whose pressure is reduced by the first external expansion valve (66). Cooled by.

  In the cooling operation to be described later, the first cabinet is such that the pressure of the refrigerant decompressed by the second external expansion valve (67) is lower than that of the refrigerant decompressed by the first external expansion valve (66). The external expansion valve (66) and the second external expansion valve (67) are controlled. For this reason, the refrigerant having a lower temperature flows in the low temperature side passage (17b) of the first cooling heat exchanger (17) than in the low temperature side passage (18b) of the second cooling heat exchanger (18).

  The first four-way switching valve (31) has a first port (P1) connected to the discharge junction pipe (21) and a second port (P2) connected to the fourth port (P4) of the second four-way switching valve (32). The third port (P3) is connected to the external heat exchanger (15), and the fourth port (P4) is connected to the first gas side shut-off valve (113). The second four-way selector valve (32) has a first port (P1) connected to the discharge branch pipe (97), a second port (P2) connected to the third suction pipe (57c), and a fourth port (P4). Are connected to the second port (P2) of the first four-way selector valve (31), respectively. The third port (P3) of the second four-way selector valve (32) is configured as a closed port. The third four-way selector valve (33) has a first port (P1) connected to the discharge junction pipe (21) and a second port (P2) connected to the second suction pipe (57b). ), The third port (P3) is connected to the second suction branch pipe (58b), and the fourth port (P4) is connected to the first suction branch pipe (58a). The fourth four-way selector valve (34) has a first port (P1) connected to the high pressure pipe (120), a second port (P2) connected to the third injection pipe (30), and a third port (P3) connected to the third port (P3). A fourth port (P4) is connected to the first injection branch pipe (49a) and the fourth injection branch pipe (49b).

  In each of the first to third four-way selector valves (31, 32, 33), the first port (P1) and the third port (P3) communicate with each other to connect the second port (P2) and the fourth port (P4). ) Communicate with each other (the state indicated by the solid line in FIG. 1), the first port (P1) and the fourth port (P4) communicate with each other, the second port (P2) and the third port (P3) Are configured to be switchable between a second state (a state indicated by a broken line in FIG. 1) in communication with each other.

  The outside unit (10) is provided with a controller (110) for controlling the compression mechanism (40), each outside expansion valve (65 to 67), and each solenoid valve (SV1 to SV4). Moreover, various sensors are provided in the outside unit (10). Specifically, the discharge junction pipe (21) is provided with a discharge pressure sensor (43). Each discharge pipe (56) is provided with a discharge temperature sensor (48a, 48b, 48c). The first suction pipe (57a) is provided with a first suction pressure sensor (71a) and a first suction temperature sensor (69a). The third suction pipe (57c) is provided with a second suction pressure sensor (71b) and a second suction temperature sensor (69b). The second liquid pipe (25) is provided with a first liquid temperature sensor (106) and a second liquid temperature sensor (107). A first intermediate pressure temperature sensor (108) is provided in the first injection pipe (28). The second injection pipe (29) is provided with a second intermediate pressure temperature sensor (109). In addition, an outside air temperature sensor (46) is provided in the vicinity of the external fan (23). The detection values of these sensors are input to the controller (110).

《Indoor unit》
In the indoor circuit (52), an indoor expansion valve (53) and an indoor heat exchanger (54) are provided in order from the liquid side end to the gas side end. The indoor expansion valve (53) is an electronic expansion valve whose opening degree can be adjusted. The indoor heat exchanger (54) is a cross-fin fin-and-tube heat exchanger. The indoor heat exchanger (54) constitutes a first usage side heat exchanger (54). An indoor fan (55) that sends indoor air to the indoor heat exchanger (54) is provided in the vicinity of the indoor heat exchanger (54). In the indoor heat exchanger (54), heat is exchanged between the refrigerant and the room air.

  In the indoor unit (50), an ice melting operation for melting frost attached to the indoor heat exchanger (54) is performed only when a predetermined condition is satisfied. The predetermined condition is, for example, a condition that the detected value of the heat exchange temperature sensor (121) that measures the surface temperature of the indoor heat exchanger (54) is lower than a predetermined value (for example, 0 ° C.). In the ice melting operation, the indoor expansion valve (53) is set to the closed state, and the operation of the indoor fan (55) is continued. In this indoor unit (50), the indoor expansion valve (53) is controlled so that frost does not adhere to the indoor heat exchanger (54), but frost has adhered to the indoor heat exchanger (54). In some cases, an ice melting operation is performed as an emergency operation.

Refrigeration unit, refrigeration unit
In the first internal circuit (61a) and the second internal circuit (61b), the internal expansion valve (63a, 63b) and the internal heat exchanger (64a, 64b) are provided. Each internal expansion valve (63a, 63b) is configured by an electronic expansion valve whose opening degree is adjustable. Each of the internal heat exchangers (64a, 64b) is configured by a cross fin type fin-and-tube heat exchanger. Each internal heat exchanger (64a, 64b) constitutes a second usage side heat exchanger (64). In the vicinity of the internal heat exchangers (64a, 64b), internal fans (65a, 65b) for supplying internal air to the internal heat exchangers (64a, 64b) are provided. In each internal heat exchanger (64a, 64b), heat is exchanged between the refrigerant and the internal air.

  In the refrigeration unit (60a) and the refrigeration unit (60b), an ice melting operation for melting frost adhering to the internal heat exchanger (64) is performed periodically (for example, every 3 hours). In the ice melting operation, the internal expansion valve (63) is set to the closed state, and the operation of the internal fan (65) is continued. In addition, you may use heating means, such as an electric heater, for the cooling of the ice adhering to the internal heat exchanger (64). In the refrigeration unit (60a) and the refrigeration unit (60b), since the evaporation temperature of the refrigerant is low, frost adheres to the internal heat exchanger (64) during operation. For this reason, the ice melting operation is periodically performed.

《Booster unit》
The booster circuit (81) is provided with a booster compressor (86). The discharge pipe (78) of the booster compressor (86) is provided with an oil separator (87), a high pressure switch (88), and a check valve (CV15) in order from the booster compressor (86) side. . An oil return pipe (92) provided with a capillary tube (91) is connected to the oil separator (87). The booster circuit (81) is provided with a bypass pipe (95) that bypasses the booster compressor (86). The bypass pipe (95) is provided with a check valve (CV14).

<Compressor configuration>
The structure of each compressor (14a, 14b, 14c) is demonstrated according to FIG.2 and FIG.3. In addition, since each compressor (14a, 14b, 14c) is the same structure, the structure of a 1st compressor (14a) is demonstrated here.

  The first compressor (14a) includes a vertically long and sealed casing-like casing (70). Inside the casing (70), an electric motor (85) and a fluid machine (82) are arranged from bottom to top.

  The electric motor (85) includes a stator (83) and a rotor (84). The stator (83) is fixed to the body of the casing (70). On the other hand, the rotor (84) is disposed inside the stator (83), and is connected to the crankshaft (90).

  The fluid machine (82) includes a movable scroll (76) and a fixed scroll (75). The movable scroll (76) includes a substantially disc-shaped movable side end plate (76b) and a spiral movable side wrap (76a). The movable side wrap (76a) is erected on the front surface (upper surface) of the movable side end plate (76b). A cylindrical protrusion (76c) into which the eccentric part of the crankshaft (90) is inserted is erected on the back surface (lower surface) of the movable side end plate (76b). The movable scroll (76) is supported by the housing (77) disposed below the movable scroll (76) via the Oldham ring (79). On the other hand, the fixed scroll (75) includes a substantially disc-shaped fixed side end plate (75b) and a spiral fixed side wrap (75a). The fixed side wrap (75a) is erected on the front surface (lower surface) of the fixed side end plate (75b). In the fluid machine (82), the fixed side wrap (75a) and the movable side wrap (76a) mesh with each other to form a plurality of compression chambers (73) between the contact portions of both wraps (75a, 76a). ing.

  In addition, in each compressor (14) of this embodiment, what is called asymmetrical spiral structure is employ | adopted, and the number of windings (spiral length) is different by the fixed side wrap (75a) and the movable side wrap (76a). ing. The plurality of compression chambers (73) includes a first compression chamber (73a) configured between an inner peripheral surface of the fixed side wrap (75a) and an outer peripheral surface of the movable side wrap (76a), and a fixed side wrap ( 75a) and a second compression chamber (73b) configured between the outer peripheral surface of the movable side wrap (76a).

  In the fluid machine (82), a suction port (98) is formed at the outer edge of the fixed scroll (75). A first suction pipe (57a) that penetrates the top of the casing (70) is connected to the suction port (98). The suction port (98) intermittently communicates with each of the first compression chamber (73a) and the second compression chamber (73b) as the movable scroll (76) revolves. The suction port (98) is provided with a suction check valve (not shown) that prohibits the flow of refrigerant from the compression chamber (73) back to the first suction pipe (57a).

  Further, in the fluid machine (82), the discharge port (93) is formed at the center of the fixed side end plate (75b). The discharge port (93) intermittently communicates with each of the first compression chamber (73a) and the second compression chamber (73b) as the movable scroll (76) revolves. The discharge port (93) opens into a muffler space (96) formed above the fixed scroll (75).

  Further, an intermediate pressure port (99) to which the second injection pipe (29) is connected is formed in the fixed side end plate (75b) of the fluid machine (82). The intermediate pressure port (99) is formed so as to straddle the fixed-side wrap (75a) at a position between the center and the outer periphery of the fixed-side end plate (75b). The intermediate pressure port (99) communicates with both the intermediate pressure first compression chamber (73a) and the intermediate pressure second compression chamber (73b).

  The casing (70) is partitioned into an upper suction space (101) and a lower discharge space (100) by a disk-shaped housing (77). The suction space (101) communicates with the suction port (98) through a communication port (not shown). The discharge space (100) communicates with the muffler space (96) through a communication passage (103) formed between the fixed scroll (75) and the housing (77). Since the refrigerant discharged from the discharge port (93) flows through the muffler space (96), the discharge space (100) during operation becomes a high-pressure space filled with the refrigerant compressed by the fluid machine (82). In the discharge space (100), a first discharge pipe (56a) that penetrates the body of the casing (70) is opened.

  An oil sump for storing refrigeration oil is formed at the bottom of the casing (70). A first oil supply passage (104) that opens to the oil sump is formed inside the crankshaft (90). In addition, a second oil supply passage (105) connected to the first oil supply passage (104) is formed in the movable side end plate (76b). In the compressor (14), the refrigeration oil in the oil reservoir is supplied to the low pressure side of the compression chamber (73) through the first oil supply passage (104) and the second oil supply passage (105).

-Driving action-
Next, the operation performed by the refrigeration apparatus (1) will be described for each operation. The refrigeration apparatus (1) is configured to be able to set eight types of operation modes. Specifically, <i> cooling operation that only cools the indoor unit (50), <ii> heating operation that only heats the indoor unit (50), <iii> refrigeration unit (60a) and refrigeration unit (60b) ) Refrigeration / freezing operation that only cools the inside of the cabinet at <1>, <iv> First cooling / cooling operation that cools the inside unit (50) with the cooling of the refrigerator unit (60a) and the freezing unit (60b) <V> Second cooling / cooling operation when the cooling capacity of the indoor unit (50) is insufficient during the first cooling / cooling operation, <vi> Refrigeration unit (60a) without using the external heat exchanger (15) ) And the first cooling and heating operation for cooling the inside of the refrigerator in the refrigeration unit (60b) and the heating in the indoor unit (50), and <vii> the heating capacity of the indoor unit (50) is excessive in the first cooling and heating operation. Sometimes the second cooling and heating operation, and <viii> the first cooling and heating operation, the heating capacity of the indoor unit (50) is insufficient. Third cooling heating operation performed can is configured to be selected. In the refrigeration apparatus (1), the first cooling cooling operation and the second cooling cooling operation correspond to the cooling operation according to the present invention.

<Cooling operation>
In the cooling operation, as shown in FIG. 4, with the first four-way switching valve (31) and the second four-way switching valve (32) both set to the first state, the third compressor (14c) Driving is performed. In the cooling operation, when the cooling capacity is insufficient, the second compressor (14b) is also operated. At that time, the third four-way selector valve (33) is set to the second state, and the second compressor (14b) constitutes an indoor compressor. The first compressor (14a) is always stopped.

  During the cooling operation, the degree of superheat of the indoor expansion valve (53) is controlled so that the degree of superheat of the refrigerant at the outlet of the indoor heat exchanger (54) becomes a predetermined value (5 ° C.), for example. This is the same in the following cooling operation. Each internal expansion valve (63) is set in a closed state. In the cooling operation, a vapor compression refrigeration cycle is performed in which the external heat exchanger (15) serves as a condenser and the indoor heat exchanger (54) serves as an evaporator.

  Specifically, in the cooling operation, the refrigerant discharged from the third compressor (14c) is condensed in the external heat exchanger (15), and flows into the indoor circuit (52) through the receiver (16). In the indoor circuit (52), the refrigerant flowing in is depressurized by the indoor expansion valve (53), and then absorbs heat from the indoor air by the indoor heat exchanger (54) and evaporates. The indoor air cooled by the refrigerant is supplied to the store space. The refrigerant evaporated in the indoor heat exchanger (54) is sucked into the third compressor (14c) and discharged again. In addition, the evaporation temperature of the refrigerant | coolant in an indoor heat exchanger (54) is set, for example to 10 degreeC.

<Heating operation>
In the heating operation, as shown in FIG. 5, the third four-way switching valve (31) is set to the second state and the second four-way switching valve (32) is set to the first state. The compressor (14c) is operated. In the heating operation, when the heating capacity is insufficient, the second compressor (14b) is also operated. At that time, the third four-way selector valve (33) is set to the second state. The first compressor (14a) is always stopped.

  During the heating operation, the opening degree of the indoor expansion valve (53) is controlled to be subcooled so that, for example, the degree of supercooling of the refrigerant at the outlet of the indoor heat exchanger (54) becomes a predetermined value (5 ° C.). This is the same in the following heating operation. Each internal expansion valve (63) is set in a closed state. In the heating operation, a vapor compression refrigeration cycle is performed in which the indoor heat exchanger (54) is a condenser and the external heat exchanger (15) is an evaporator.

  Specifically, the refrigerant discharged from the third compressor (14c) flows into the indoor circuit (52), dissipates heat to the indoor air in the indoor heat exchanger (54), and condenses. The room air heated by the refrigerant is supplied to the store space. The refrigerant condensed in the indoor heat exchanger (54) is depressurized by the third external expansion valve (65), evaporated by the external heat exchanger (15), and sucked into the third compressor (14c). It is discharged again.

<Refrigeration operation>
In the refrigeration operation, as shown in FIG. 6, the first compressor (14a) is operated with the first four-way switching valve (31) set to the first state. In the refrigeration operation, when the cooling capacity in the warehouse is insufficient, the second compressor (14b) is also operated. At that time, the third four-way selector valve (33) is set to the first state, and the second compressor (14b) constitutes an internal compressor. The third compressor (14c) is always stopped.

  During the refrigeration operation, the degree of superheat of each opening degree of the internal expansion valve (63) is controlled. This point is the same also in the operation | movement which cools the following store | warehouse | chambers. The indoor expansion valve (53) is set in a closed state. In the refrigeration operation, a vapor compression refrigeration cycle is performed in which the external heat exchanger (15) serves as a condenser and each internal heat exchanger (64) serves as an evaporator.

  Specifically, in the refrigeration operation, the refrigerant discharged from the first compressor (14a) is condensed in the external heat exchanger (15). The refrigerant condensed in the external heat exchanger (15) is distributed to the first internal circuit (61a) and the second internal circuit (61b) via the receiver (16).

  In the first internal circuit (61a), the inflowing refrigerant is depressurized by the internal expansion valve (63a), and then absorbs heat from the internal air by the internal heat exchanger (64a) to evaporate. The inside air cooled by the refrigerant is supplied to the inside of the refrigerated showcase. In the second internal circuit (61b), the refrigerant that has flowed in is decompressed by the internal expansion valve (63b) and then absorbs heat from the internal air in the internal heat exchanger (64b) to evaporate. The internal air cooled by the refrigerant is supplied into the freezer showcase. The refrigerant evaporated in the internal heat exchanger (64b) is compressed by the booster compressor (86). Then, the refrigerant evaporated in the internal heat exchanger (64a) and the refrigerant compressed by the booster compressor (86) are sucked into the first compressor (14a) and discharged again after joining.

  In the refrigeration operation, the evaporation temperature of the refrigerant in the internal heat exchanger (64a) is set to, for example, −5 ° C., and the evaporation temperature of the refrigerant in the internal heat exchanger (64b) is set to, for example, −30 ° C. Is set.

<First cooling and cooling operation>
In the first cooling and cooling operation, as shown in FIG. 7, the first compressor (31) and the second four-way switching valve (32) are both set to the first state. 14a) and the third compressor (14c) are operated. In the first cooling and cooling operation, when the cooling capacity in the warehouse is insufficient, the second compressor (14b) is also operated. At that time, the third four-way selector valve (33) is set to the first state, and the second compressor (14b) constitutes an internal compressor. In the first cooling and cooling operation, a vapor compression refrigeration cycle is performed in which the external heat exchanger (15) serves as a condenser and the indoor heat exchanger (54) and each internal heat exchanger (64) serve as an evaporator. .

  Specifically, in the first cooling and cooling operation, the refrigerant discharged from the first compressor (14a) and the third compressor (14c) is condensed in the external heat exchanger (15). The refrigerant condensed in the external heat exchanger (15) is distributed to the first internal circuit (61a), the second internal circuit (61b), and the indoor circuit (52) through the receiver (16). The

  The refrigerant distributed to the first internal circuit (61a) and the second internal circuit (61b) flows in the same flow as in the refrigeration operation, and is sucked into the first compressor (14a) and discharged again. . The refrigerant distributed to the indoor circuit (52) flows in the same flow as in the cooling operation, and is sucked into the third compressor (14c) and discharged again.

  In the first cooling / cooling operation, the refrigerant evaporation temperature in the indoor heat exchanger (54) is set to 10 ° C., for example, and the refrigerant evaporation temperature in the internal heat exchanger (64a) is set to −5 ° C., for example. The evaporating temperature of the refrigerant in the internal heat exchanger (64b) is set to, for example, −30 ° C. The refrigerant evaporation temperature in the indoor heat exchanger (54) is set to a value higher than the refrigerant evaporation temperature in the internal heat exchanger (64). This point is the same in the following second cooling and cooling operation. In the cooling / cooling operation, as shown in FIG. 8, the low pressure of the refrigeration cycle on the refrigeration and freezing side is lower than the low pressure of the refrigeration cycle on the cooling side. The intermediate pressure of the refrigeration cycle on the refrigeration and freezing side is lower than the intermediate pressure of the refrigeration cycle on the cooling side.

<Second cooling and cooling operation>
The second cooling and cooling operation is performed by switching the third four-way switching valve (33) to the second state when the cooling capacity is insufficient in the first cooling and cooling operation. In the second cooling and cooling operation, the second compressor (14b) is switched to the indoor unit (50) side. That is, the second compressor (14b) constitutes an indoor compressor. The settings for the second cooling / air-cooling operation are basically the same as those for the first cooling / air-cooling operation except for the third four-way switching valve (33).

<First cooling and heating operation>
In the first cooling / heating operation, as shown in FIG. 9, the first four-way selector valve (31) is set to the second state and the second four-way selector valve (32) is set to the first state. The first compressor (14a) is operated. In the first cooling / heating operation, when the cooling capacity in the warehouse is insufficient, the second compressor (14b) is also operated. At that time, the third four-way selector valve (33) is set to the first state. In the first cooling and heating operation, a vapor compression refrigeration cycle is performed in which the indoor heat exchanger (54) serves as a condenser and the internal heat exchanger (64) serves as an evaporator. During the first cooling / heating operation, the cooling capacity (evaporation heat amount) of the refrigeration unit (60a) and the refrigeration unit (60b) balances with the heating capacity (condensation heat amount) of the indoor unit (50), and 100% heat is obtained. Recovery is performed.

  Specifically, the refrigerant discharged from the first compressor (14a) dissipates heat to the indoor air and condenses in the indoor heat exchanger (54). The refrigerant condensed in the indoor heat exchanger (54) is distributed to the first internal circuit (61a) and the second internal circuit (61b), respectively. The refrigerant distributed to the first internal circuit (61a) and the second internal circuit (61b) flows in the same flow as in the refrigeration operation, and is sucked into the first compressor (14a) and discharged again. .

<Second cooling and heating operation>
The second cooling / heating operation is performed by switching the second four-way switching valve (32) to the second state as shown in FIG. 10 when the heating capacity is surplus during the first cooling / heating operation. . In the second cooling / heating operation, the external heat exchanger (15) functions as a condenser. The setting during the second cooling / air-heating operation is basically the same as the first cooling / air-heating operation except for the second four-way switching valve (32).

  In the second cooling / heating operation, a part of the refrigerant discharged from the first compressor (14a) flows into the external heat exchanger (15). In the external heat exchanger (15), the refrigerant flowing in dissipates heat to the external air and condenses. The refrigerant condensed in the external heat exchanger (15) merges with the refrigerant condensed in the indoor heat exchanger (54) and is distributed to the first internal circuit (61a) and the second internal circuit (61b), respectively. Is done. In the second cooling / heating operation, the cooling capacity (evaporation heat amount) of the refrigeration unit (60a) and the refrigeration unit (60b) and the heating capacity (condensation heat amount) of the indoor unit (50) are not balanced, and the remaining condensation heat. Is discharged from the external heat exchanger (15).

<Third cooling and heating operation>
In the third cooling and heating operation, when the heating capacity is insufficient during the first cooling and heating operation, the second four-way switching valve (32) is set to the first state as shown in FIG. This is done by operating the three compressor (14c). In the third cooling and heating operation, a vapor compression refrigeration cycle is performed in which the indoor heat exchanger (54) serves as a condenser, and the internal heat exchanger (64) and the external heat exchanger (15) serve as an evaporator. .

  In the third cooling / heating operation, the refrigerant condensed in the indoor heat exchanger (54) is not only in the first internal circuit (61a) and the second internal circuit (61b) but also in the external heat exchanger (15) side. Distributed to. The refrigerant distributed to the external heat exchanger (15) is depressurized by the third external expansion valve (65) and then evaporated by the external heat exchanger (15) to the third compressor (14c). Inhaled and discharged again. In the third cooling / heating operation, the cooling capacity (heat evaporation amount) of the refrigeration unit (60a) and the refrigeration unit (60b) and the heating capacity (condensation heat amount) of the indoor unit (50) are not balanced, and insufficient evaporation. Heat is absorbed by the external heat exchanger (15).

<Injection operation>
In the present embodiment, an injection operation is performed in which an intermediate pressure refrigerant is injected into the intermediate pressure compression chamber (73) of the compressor (14) during operation. Hereinafter, the injection operation when both the internal compressor (14a, 14b) and the indoor compressor (14b, 14c) are operating will be described.

  In the injection operation, the first external expansion valve (66) is set to the open state. The opening degree of the first external expansion valve (66) is larger than the internal pressure of the compression chamber (73) in which the intermediate pressure port (99) opens among the intermediate pressure compression chamber (73) of the third compressor (14c). It is controlled by the controller (110) so as to obtain a high pressure. Note that the controller (110) is configured based on, for example, the pressure of the refrigerant on the suction side of the third compressor (14c) (specifically, the measured value of the second suction pressure sensor (71b)). 14c) Estimate the internal pressure of the intermediate pressure compression chamber (73).

  When the first external expansion valve (66) is set to the open state, a part of the refrigerant flowing through the second liquid pipe (25) flows into the first injection pipe (28) as shown in FIG. In the first injection pipe (28), the refrigerant that has flowed in is decompressed by the first external expansion valve (66). In the first external expansion valve (66), the pressure in the intermediate pressure compression chamber (73) of the third compressor (14c) is higher than the internal pressure of the compression chamber (73) in which the intermediate pressure port (99) opens. The refrigerant is depressurized and the temperature of the refrigerant decreases. The refrigerant decompressed by the first external expansion valve (66) exchanges heat with the refrigerant flowing through the second liquid pipe (25) in the second cooling heat exchanger (18). In the second cooling heat exchanger (18), the refrigerant in the first injection pipe (28) is heated and evaporates, while the refrigerant flowing in the second liquid pipe (25) is cooled to be in a supercooled state. The refrigerant evaporated in the second cooling heat exchanger (18) merges with the refrigeration oil in the third oil return pipe (38c), and then the intermediate pressure compression chamber (73) in the third compressor (14c). Flow into. In the present embodiment, the oil droplets are mixed with the refrigerant flowing into the compression chamber (73) of the intermediate pressure of each compressor (14), so that the sound when the refrigerant flows in can be reduced.

  In the injection operation, the second external expansion valve (67) is set to the open state. The opening degree of the second external expansion valve (67) is larger than the internal pressure of the compression chamber (73) in which the intermediate pressure port (99) is opened in the intermediate pressure compression chamber (73) of the third compressor (14c). The pressure is lower than the high pressure and is higher than the internal pressure of the compression chamber (73) in which the intermediate pressure port (99) is opened in the compression chamber (73) of the intermediate pressure of the first compressor (14a). It is controlled by the controller (110). Note that the controller (110) is configured based on, for example, the pressure of the refrigerant on the suction side of the first compressor (14a) (specifically, the measured value of the first suction pressure sensor (71a)). 14a) Estimate the internal pressure of the intermediate pressure compression chamber (73). The opening degree of the second external expansion valve (67) is such that the pressure of the refrigerant after depressurization by the second external expansion valve (67) is downstream of the first external expansion valve (66) in the first injection pipe (28). The pressure is controlled to be lower than that of the refrigerant.

  When the second external expansion valve (67) is set to the open state, a part of the refrigerant flowing through the first injection pipe (28) flows into the second injection pipe (29). In the second injection pipe (29), the refrigerant that has flowed in is decompressed by the second external expansion valve (67). In the second external expansion valve (67), the pressure is higher than the internal pressure of the compression chamber (73) in which the intermediate pressure port (99) opens out of the intermediate pressure compression chamber (73) of the first compressor (14a). The refrigerant is depressurized and the temperature of the refrigerant decreases. The temperature of the refrigerant decompressed by the second external expansion valve (67) is lower than that of the refrigerant decompressed by the first external expansion valve (66). The refrigerant decompressed by the second external expansion valve (67) exchanges heat with the refrigerant flowing through the second liquid pipe (25) in the first cooling heat exchanger (17). In the first cooling heat exchanger (17), the refrigerant in the second injection pipe (29) is heated and evaporates, while the refrigerant flowing through the second liquid pipe (25) is further cooled to increase the degree of supercooling. The refrigerant evaporated in the first cooling heat exchanger (17) merges with the refrigeration oil in the first oil return pipe (38a), and then the intermediate pressure compression chamber (73) in the first compressor (14a). Flow into.

  By performing the injection operation, in the second cooling heat exchanger (18), the refrigerant supplied to the indoor unit (50), the refrigeration unit (60a), and the refrigeration unit (60b) is brought to a temperature of 20 ° C., for example. To be cooled. The first branch pipe (26) communicating with the indoor unit (50) is branched from between the first cooling heat exchanger (17) and the second cooling heat exchanger (18), so that the indoor unit (50) The refrigerant flows at about 20 ° C. In the indoor unit (50), the refrigerant at about 20 ° C. is decompressed by the indoor expansion valve (53) to, for example, 10 ° C., and the 10 ° C. refrigerant flows into the indoor heat exchanger (54).

  Furthermore, by performing the injection operation, in the first cooling heat exchanger (17), the refrigerant supplied to the refrigeration unit (60a) and the refrigeration unit (60b) is cooled to a temperature of 0 ° C., for example. About 0 ° C. refrigerant flows into the refrigeration unit (60a) and the refrigeration unit (60b). In the refrigeration unit (60a), the refrigerant at about 0 ° C. is depressurized by the internal expansion valve (63a) to, for example, −5 ° C., and the −5 ° C. refrigerant flows into the internal heat exchanger (64a). To do. In the refrigeration unit (60b), the refrigerant at about 0 ° C. is depressurized by the internal expansion valve (63b) to, for example, −30 ° C., and the −30 ° C. refrigerant flows into the internal heat exchanger (64b).

  In the present embodiment, if the second compressor (14b) is in operation, the intermediate pressure refrigerant is also injected into the intermediate pressure compression chamber (73) of the second compressor (14b). When the second compressor (14b) constitutes an indoor compressor, the refrigerant from the first injection pipe (28) is injected. On the other hand, when the second compressor (14b) constitutes the internal compressor, the refrigerant from the second injection pipe (29) is injected.

  Specifically, when the third four-way selector valve (33) is set to the second state and switched from the first cooling cooling operation to the second cooling cooling operation, as shown in FIG. The path switching valve (34) is set to the second state. In this case, the second compressor (14b) constitutes an indoor compressor, the suction side of the second compressor (14b) communicates with the indoor heat exchanger (54), and the second compressor (14b) is intermediate between the second compressor (14b). The pressure compression chamber (73) communicates with the first injection pipe (28) through the first injection branch pipe (49a). As a result, a part of the intermediate pressure refrigerant flowing through the first injection pipe (28) flows into the third injection pipe (30) through the first injection branch pipe (49a), and the second compressor (14b) It is injected into a compression chamber (73) of intermediate pressure.

  Further, when the third four-way selector valve (33) is set to the first state during the first cooling / cooling operation, as shown in FIG. 13, the fourth four-way selector valve (34) is the first one. Set to state. In this case, the second compressor (14b) constitutes an internal compressor, the suction side of the second compressor (14b) communicates with the internal heat exchanger (64), and the second compressor (14b) The intermediate pressure compression chamber (73) communicates with the second injection pipe (29) through the second injection branch pipe (49b). As a result, part of the intermediate pressure refrigerant flowing through the second injection pipe (29) flows into the third injection pipe (30) through the second injection branch pipe (49b), and the second compressor (14b) It is injected into a compression chamber (73) of intermediate pressure. In this embodiment, when the second compressor (14b) is used as an internal compressor, the refrigerant decompressed by the first external expansion valve (66) and the second external expansion valve (67) The refrigerant having the lower pressure among the refrigerant depressurized in is injected.

  In this refrigeration system (1), when only the indoor compressor (14b, 14c) is in operation, for example during cooling operation, the intermediate pressure compression chamber (73) of the indoor compressor (14b, 14c) An injection operation for injecting an intermediate pressure refrigerant is performed. In addition, when only the internal compressor (14a, 14b) is in operation, such as during refrigeration, the intermediate pressure refrigerant is stored in the intermediate pressure compression chamber (73) of the internal compressor (14a, 14b). Injecting operation is performed.

-Effect of the embodiment-
In the present embodiment, the first cooling heat for cooling only the refrigerant supplied to the indoor heat exchanger (64) having the lower evaporation temperature of the indoor heat exchanger (54) and the internal heat exchanger (64). Since the exchanger (17) is provided, regardless of the refrigerant evaporation temperature in the indoor heat exchanger (54) having the higher evaporation temperature, the first cooling heat exchanger (17) is used to heat the internal heat exchanger (64 ) Is cooled. For this reason, compared with the conventional structure with which the temperature of the refrigerant | coolant supplied to an indoor heat exchanger (54) and the temperature of the refrigerant | coolant supplied to an internal heat exchanger (64) become substantially equal, the internal heat exchanger The temperature of the refrigerant supplied to (64) can be lowered. Therefore, the cooling capacity in the internal heat exchanger (64) can be improved, and the operating efficiency of the refrigeration apparatus (1) can be improved.

  Further, when the temperature of the refrigerant supplied to the internal heat exchanger (64) is lowered, the density of the refrigerant supplied to the internal heat exchanger (64) increases (the volume flow rate decreases). Therefore, since the pressure loss when the refrigerant supplied to the internal heat exchanger (64) is depressurized can be reduced, the operating efficiency of the refrigeration apparatus (1) can also be improved.

  Moreover, in this embodiment, the refrigerant | coolant supplied to the in-compartment heat exchanger (64) with a lower evaporation temperature can be cooled with a 1st cooling heat exchanger (17). Here, even in the conventional configuration in which the temperature of the refrigerant supplied to the first usage-side heat exchanger (54) and the temperature of the refrigerant supplied to the internal heat exchanger (64) are substantially equal, If it is in the range of restriction by the evaporation temperature of the refrigerant in the indoor heat exchanger (54), the cooling capacity in the internal heat exchanger (64) becomes larger when the refrigerant is cooled to a lower temperature. However, when the cooling capacity in the internal heat exchanger (64) is increased, there arises a problem that frost tends to adhere to the indoor heat exchanger (54) that is desired to prevent frost formation. On the other hand, in this embodiment, since the refrigerant | coolant supplied to a heat exchanger (64) in a store | warehouse | chamber by the 1st cooling heat exchanger (17) can be cooled, a 2nd cooling heat exchanger (18) It is not necessary to cool the refrigerant to such a low temperature. For this reason, frost formation in the indoor heat exchanger (54) can be suppressed.

  In the present embodiment, the second cooling pipe (25) is provided with the second cooling heat exchanger (18), so that the indoor heat exchanger (54) is cooled by the second cooling heat exchanger (18). A refrigerant is supplied. For this reason, since the temperature of the refrigerant | coolant supplied to an indoor heat exchanger (54) can be reduced compared with the case where a 2nd cooling heat exchanger (18) is not provided, cooling in an indoor heat exchanger (54) The capacity can be improved, and the operating efficiency of the refrigeration apparatus (1) can be improved.

  In the present embodiment, the refrigerant supplied to the internal heat exchanger (64) includes the refrigerant in the low temperature side circuit (17b) of the first cooling heat exchanger (17) and the second cooling heat exchanger (18). Among the refrigerants in the low temperature side circuit (18b), heat exchange is performed in order from the refrigerant having the higher temperature. Therefore, in both the first cooling heat exchanger (17) and the second cooling heat exchanger (18), the cooled refrigerant supplied to the internal heat exchanger (64) and the low-temperature circuit ( A relatively large temperature difference can be secured between the refrigerant on the cooling side of 17b and 18b). Therefore, since the heat exchange efficiency in the whole of the first cooling heat exchanger (17) and the second cooling heat exchanger (18) is improved, the temperature of the refrigerant supplied to the internal heat exchanger (64) is further reduced. The cooling capacity of the internal heat exchanger (64) can be further increased.

-Modification of the embodiment-
A modification of this embodiment will be described. In this modification, as shown in FIG. 14, in addition to the first cooling heat exchanger (17) and the second cooling heat exchanger (18), a third cooling heat exchanger (19) is provided.

  Specifically, the third injection pipe (30) branches from the connection injection pipe (9). The third injection pipe (30) is connected to the intermediate pressure compression chamber (73) of the second compressor (14b) at the end opposite to the one connected to the connection injection pipe (9). The third injection pipe (30) is provided with a fourth external expansion valve (68) constituted by an electronic expansion valve having a variable opening.

  Further, the third branch pipe (47) branched from the first injection pipe (28) is provided with a fifth external expansion valve (72) constituted by an electronic expansion valve having a variable opening. In the third branch pipe (47), a fifth electromagnetic valve (SV5) is provided in parallel with the fifth external expansion valve (72).

  In the second branch pipe (27), the second pipe provided with the third cooling heat exchanger (19) in parallel with the first pipe (27a) provided with the first cooling heat exchanger (17). (27b) is provided. That is, in the second branch pipe (27), the third cooling heat exchanger (19) is provided in parallel with the first cooling heat exchanger (17). The third cooling heat exchanger (19) is provided so as to straddle the second pipe (27b) and the third injection pipe (30).

  In the third cooling heat exchanger (19), heat exchange is performed between the refrigerant downstream of the fourth external expansion valve (68) in the third injection pipe (30) and the refrigerant flowing in the second pipe (27b). Is called. In the third cooling heat exchanger (19), the refrigerant flowing through the second pipe (27b) is cooled by the intermediate-pressure refrigerant decompressed by the fourth external expansion valve (68).

  In this modification, unlike the above embodiment, the third compressor (14c) is configured by an inverter compressor having a variable operating capacity. A gas vent pipe (48) extending from the receiver (16) is connected to the first suction pipe (57a).

  In this modification, during the injection operation during operation of the second compressor (14b), the opening degree of the fourth external expansion valve (68) is such that the compression chamber of the intermediate pressure of the second compressor (14b). The controller (110) controls the pressure so that the intermediate pressure port (99) is higher than the internal pressure of the compression chamber (73) in (73). When the second compressor (14b) constitutes an internal compressor, the internal pressure of the intermediate pressure compression chamber (73) of the second compressor (14b) is the third compression constituting the indoor compressor. It becomes lower than the internal pressure of the compression chamber (73) of the intermediate pressure of the machine (14c). Therefore, when the second compressor (14b) constitutes the internal compressor, the intermediate pressure compression chamber (73) of the second compressor (14b) is provided in the same manner as the first compressor (14a). Since the refrigerant having a relatively low temperature is injected, the temperature of the refrigerant discharged from the second compressor (14b) can be effectively suppressed.

<< Other Embodiments >>
About the said embodiment, it is good also as following structures.

  About the said embodiment, in the liquid side connection piping (2b) connected to a refrigeration unit (60a) and a refrigeration unit (60b), it connects to the refrigeration side branch pipe connected to a refrigeration unit (60a), and a refrigeration unit (60b) You may provide a cooling heat exchanger only in a freezing side branch pipe among freezing side branch pipes. In this case, the refrigeration unit (60a) and the internal heat exchanger (64a) constitute a first use side heat exchanger, and the refrigeration unit (60b) and the internal heat exchanger (64b) constitute a second use side heat exchanger. Configure the vessel.

  Moreover, about the said embodiment, the structure which does not provide a 1st cooling heat exchanger (17) in a 1st branch pipe (26) may be sufficient. In this case, the intermediate pressure refrigerant having a high wetness is injected into the intermediate pressure compression chamber (73) of the indoor compressor (14b, 14c) through the first injection pipe (28). Moreover, the structure which does not provide a 2nd cooling heat exchanger (18) in a 1st branch pipe (26) may be sufficient. In this case, the intermediate pressure refrigerant having a high wetness is injected into the intermediate pressure compression chamber (73) of the internal compressor (14a, 14b) through the second injection pipe (29).

  Moreover, about the said embodiment, the compression mechanism (40) may be comprised from two compressors, a 1st compressor (14a) and a 2nd compressor (14b). In this case, the first compressor (14a) constitutes a compressor dedicated to the interior, and the second compressor (14b) constitutes a combined compressor.

  Moreover, about the said embodiment, the compressor (14) may be a compressor of a symmetrical spiral structure, and the compressor (14) may be compressors other than a scroll compressor.

  Moreover, about the said embodiment, the 1st branch pipe (26) may branch from between the 2nd cooling heat exchanger (18) and the receiver (16). In this case, since the temperature of the refrigerant supplied to the indoor heat exchanger (54) during the cooling operation is higher than that in the above embodiment, it is possible to further suppress frost from adhering to the indoor heat exchanger (54). it can.

  Moreover, about the said embodiment, the opposite end to the indoor circuit (52) in the 1st liquid side connection piping (2a) may be connected to the 2nd liquid side connection piping (2b). In this case, the first branch pipe (26) is not provided.

  In the above embodiment, the refrigeration apparatus (1) may be configured to perform a supercritical cycle in which the high pressure of the refrigeration cycle is set to a value higher than the critical pressure of the refrigerant. In this case, in a normal refrigeration cycle in which the high pressure of the refrigeration cycle is set to a value lower than the critical pressure of the refrigerant, a heat exchanger that serves as a condenser operates as a gas cooler.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a refrigeration apparatus having a cooling means for cooling a refrigerant from a radiator to an evaporator.

It is a refrigerant circuit figure of the refrigerating device concerning the embodiment of the present invention. It is a longitudinal section of the compressor of an embodiment. It is a cross-sectional view of the fixed scroll of the compressor of the embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of air conditioning operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of heating operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of refrigeration operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of the 1st cooling air conditioning operation in an embodiment. It is a ph diagram at the time of cooling air conditioning operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of the 1st cooling heating operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of the 2nd cooling heating operation in an embodiment. It is a refrigerant circuit figure showing the flow of the refrigerant at the time of the 3rd cooling heating operation in an embodiment. It is a refrigerant circuit figure showing the flow of a refrigerant in the case of performing injection operation to the 2nd compressor at the time of the 2nd cooling air conditioning operation in an embodiment. It is a refrigerant circuit figure showing the flow of a refrigerant in the case of performing injection operation to the 2nd compressor at the time of the 1st cooling air conditioning operation in an embodiment. It is a refrigerant circuit figure of the refrigerating device concerning the modification of the embodiment of the present invention.

Explanation of symbols

1 Refrigeration equipment
4 Refrigerant circuit
15 External heat exchanger (heat source side heat exchanger)
17 First cooling heat exchanger (cooling means after branching)
18 Second cooling heat exchanger (cooling means before branching)
24 1st liquid pipe (main liquid side passage)
25 Second liquid pipe (main liquid side passage)
26 First branch pipe (first branch passage)
27 Second branch pipe (second branch passage)
54 Indoor heat exchanger (first use side heat exchanger)
64 Internal heat exchanger (second use side heat exchanger)

Claims (4)

A compression mechanism (40), a heat source side heat exchanger (15), a first usage side heat exchanger (54), and a second usage side heat exchanger (64) are provided to circulate the refrigerant and perform the refrigeration cycle. With refrigerant circuit (4) to perform,
In the refrigerant circuit (4), the heat source side heat exchanger (15) operates as a radiator, and both the first usage side heat exchanger (54) and the second usage side heat exchanger (64) evaporate. Cooling operation that operates as a container,
In the cooling operation, the refrigerant evaporating temperature in the second usage side heat exchanger (64) is set to a temperature lower than the evaporating temperature of the refrigerant in the first usage side heat exchanger (54). And
In the cooling operation, a main liquid side passage (in which refrigerant flows from the heat source side heat exchanger (15) to the first usage side heat exchanger (54) and the second usage side heat exchanger (64) ( 24,25)
A first branch passage (26) through which refrigerant flows from the main liquid side passage (24, 25) to the first use side heat exchanger (54) during the cooling operation;
A second branch passage (27) through which refrigerant flows from the main liquid side passage (24, 25) to the second usage side heat exchanger (64) during the cooling operation;
Of the first branch passage (26) and the second branch passage (27), only the second branch passage (27) cools the refrigerant radiated by the heat source side heat exchanger (15) during the cooling operation. A refrigeration apparatus provided with post-branching cooling means (17). In claim 1,
The main liquid side passages (24, 25) are provided with pre-branch cooling means (18) for cooling the refrigerant radiated by the heat source side heat exchanger (15) during the cooling operation. Refrigeration equipment. In claim 2,
The post-branch cooling means (17) exchanges heat between the high temperature side passage through which the refrigerant in the second branch passage (27) flows and the low temperature side passage through which a refrigerant having a lower temperature than the refrigerant in the high temperature side passage flows. A first cooling heat exchanger (17) for performing
The pre-branch cooling means (18) includes a high temperature side passage through which the refrigerant in the main liquid side passage (24, 25) flows and a low temperature side passage through which a refrigerant having a lower temperature than the refrigerant in the high temperature side passage flows. While constituted by a second cooling heat exchanger (18) that performs heat exchange,
In the first cooling heat exchanger (17) and the second cooling heat exchanger (18), the first cooling heat exchanger (17) has a lower temperature refrigerant flowing in the low temperature side passage. Refrigeration equipment characterized. In claim 3,
The compression mechanism (40) includes a high-temperature compressor (14b, 14c) that sucks the refrigerant evaporated in the first usage-side heat exchanger (54), and the second usage-side heat exchanger (64). A low-temperature compressor (14a, 14b) for sucking the evaporated refrigerant,
Provided in the first injection passage (28) for injecting the refrigerant into the compression chamber of intermediate pressure of the high temperature compressor (14b, 14c), the refrigerant flowing through the first injection passage (28) is decompressed. First decompression means (66);
Refrigerant that is provided in the second injection passage (29) for injecting the refrigerant into the compression chamber (73) of intermediate pressure of the low-temperature compressor (14a, 14b) and flows through the second injection passage (29). And a second decompression means (67) for decompressing the refrigerant to a pressure lower than the refrigerant decompressed by the first decompression means (66),
The low temperature side passage of the first cooling heat exchanger (17) is disposed downstream of the second pressure reducing means (67) in the second injection passage (29), and the low temperature of the second cooling heat exchanger (18) is set. A refrigeration apparatus characterized in that a side passage is disposed downstream of the first decompression means (66) in the first injection passage (28).

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