JP2006300507A - Refrigeration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust a circulation volume in each use system without breaking down the balance between discharge and suction of each compressor. <P>SOLUTION: This refrigeration device is provided with a fixed-capacity compressor 21a for an air-conditioning unit 1D and a variable-capacity compressor 21b for cold-storage and freezer-storage showcases 1B and 1C. A supercooling heat exchanger 71 for a liquid refrigerant supplied to the air-conditioning unit 1D and the like is mounted to a connecting liquid pipe P1, and a branch refrigerant branched from the connecting liquid pipe P1 flows through the supercooling heat exchanger 71 so as to supercool the liquid refrigerant of the connecting liquid pipe P1. A three-way changeover valve 78 for changing over the passage is installed so as to guide the branch refrigerant after the supercooling to the suction side of either of the fixed-capacity compressor 21a and the variable-capacity compressor 21b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a refrigeration apparatus, and particularly relates to measures for controlling the capacity of a refrigeration apparatus that supplies the liquid refrigerant supercooled by a branched refrigerant branched from the liquid refrigerant to an air conditioning system and a cooling system.

    Conventionally, a refrigeration apparatus having a refrigerant circuit provided with a supercooling heat exchanger for supercooling liquid refrigerant is known (see, for example, Patent Document 1). In the refrigeration apparatus of Patent Document 1, an air conditioning system that cools and heats a room and a cooling system that refrigerates and freezes the interior of food and the like are connected to a heat source system having a compressor and the like to form a refrigerant circuit. ing.

Each liquid pipe of the air conditioning system and the cooling system is provided with a supercooling heat exchanger for supercooling the liquid refrigerant. Each supercooling heat exchanger is connected to a supercooling passage through which the refrigerant flows so as to supercool the liquid refrigerant in the supercooling heat exchanger with a branched refrigerant branched from the liquid refrigerant in the liquid pipe. The supercooled liquid refrigerant evaporates in the air conditioning system and the cooling system, and then is separately sucked into the dedicated compressor through each gas pipe. Thereby, the calorie | heat amount (enthalpy) of the circulating refrigerant in an air conditioning system and a cooling system increases.
JP 2004-347269 A

    However, the conventional refrigeration apparatus described above has a problem that the cooling capacity cannot be adjusted according to the magnitude relationship between the loads of the air conditioning system and the cooling system. For example, when the load in the cooling system is larger than normal and the load in the air conditioning system is smaller than normal, if the refrigerant circulation amount of the cooling system is increased by controlling an expansion valve or the like, the refrigerant circulation amount of the air conditioning system is reduced accordingly. Here, while the amount of refrigerant returning from the air-conditioning system to the dedicated compressor is reduced, all of the branched refrigerant after being supercooled by each supercooling heat exchanger passes through the supercooling passage through the suction side of the compressor dedicated to the cooling system. Therefore, the amount of suction in the compressor dedicated to the air conditioning system is reduced. That is, in the compressor dedicated to the air conditioning system, there is a problem that the balance between the discharge amount and the suction amount is lost, the efficiency is reduced, and damage is caused in the worst case.

    The present invention has been made in view of such a point, and an object of the present invention is to branch two or more utilization systems, a dedicated compressor for each utilization system, and a liquid refrigerant in a liquid pipe. In a refrigeration system equipped with a supercooling heat exchanger that supercools the liquid refrigerant in the liquid pipe with the refrigerant, the cooling load of each utilization system is maintained while maintaining a balance between the discharge amount and the suction amount of each dedicated compressor The cooling capacity is adjusted according to the above.

    In the first invention, a heat source system having a compression mechanism (2A) and a heat source side heat exchanger (23) is connected to a first usage system and a second usage system having usage side heat exchangers (31, 51). And a refrigerant circuit (10) for performing a vapor compression refrigeration cycle, wherein the compression mechanism (2A) mainly includes a first compressor (21a) for the first usage system and a second for the second usage system. A refrigeration system including a compressor (21b) is assumed. The present invention provides the liquid refrigerant in the liquid pipe (P1) that is provided in the liquid pipe (P1) of the refrigerant circuit (10) and is branched and supplied to the first usage system and the second usage system. A supercooling heat exchanger (71) for cooling, and the liquid refrigerant in the liquid pipe (P1) is connected to the supercooling heat exchanger (71) and branched from the liquid refrigerant in the liquid pipe (P1). A subcooling passage (74) for the branching refrigerant to flow through the supercooling heat exchanger (71) so as to perform supercooling, and the branching refrigerant after the supercooling in the supercooling passage (74) is the first compressor (21a). Switching means (78) for switching between a first state flowing to the suction side of the refrigerant and a second state in which the branched refrigerant after supercooling of the supercooling passage (74) flows to the suction side of the second compressor (21b) And.

    In the above invention, the liquid refrigerant in the liquid pipe (P1) supercooled by the supercooling heat exchanger (71) is distributed to the usage side heat exchangers (31, 51) of the first usage system and the second usage system. Flowing and evaporating, for example, the inside of the room or the refrigerator is cooled. Then, the refrigerant evaporated in the usage side heat exchanger (51) of the first usage system is sucked into the first compressor (21a), and the refrigerant evaporated in the usage side heat exchanger (31) of the second usage system is It is sucked into the second compressor (21b). In each use side heat exchanger (31, 51), the amount of heat (enthalpy) of the circulating refrigerant is increased by supercooling.

    Here, for example, when the cooling load in the first usage system is larger than normal and the cooling load in the second usage system is smaller than normal, the refrigerant circulation amount in the first usage system is reduced by adjusting the expansion valve and the like. (71) Increase beyond the amount of circulation before installation. As a result, in the first utilization system, the cooling capacity increases at least by the amount of heat of the refrigerant increased by the supercooling. Further, in the second usage system, the refrigerant circulation amount decreases by an amount corresponding to the increase in the refrigerant circulation amount of the first usage system, so that the cooling capacity decreases. Therefore, the cooling capacity is adjusted according to the magnitude relationship between the cooling loads in the first usage system and the second usage system.

    By the way, in the second compressor (21b), since the amount of refrigerant returning from the second utilization system is reduced, the balance between the discharge amount and the suction amount is lost, and not only the efficiency is lowered, but there is a possibility that the second compressor (21b) may be damaged. However, in the present invention, the flow path switching means (78) is switched to the second state, and the branch refrigerant in the supercooling passage (74) subcooled by the supercooling heat exchanger (71) becomes the second compressor (21b). Inhaled towards. Thereby, since the refrigerant | coolant suction | inhalation amount in a 2nd compressor (21b) increases, discharge amount and suction | inhalation amount balance. Further, when the cooling load of the first usage system is smaller than normal and the cooling load of the second usage system is larger than normal, the refrigerant circulation amount in the first usage system decreases and the refrigerant circulation amount in the second usage system increases. . In this case, the flow path switching means (78) is switched to the first state, and the branched refrigerant in the supercooling passage (74) is sucked toward the first compressor (21a).

    That is, the present invention mainly takes charge of the other utilization system in which the refrigerant circulation amount is reduced in the branch refrigerant used for the supercooling of the liquid refrigerant, instead of increasing the refrigerant circulation amount in one utilization system and increasing the cooling capacity. The compressor is returned to the compressor (21a, 21b).

    According to a second aspect of the present invention, in the first aspect of the present invention, the supercooling passage (74) has an expansion mechanism (75), and the supercooling heat exchanger removes the liquid phase branch refrigerant from the liquid pipe (P1). An upstream passage (74a) leading to (71) and a downstream passage (74b) into which the subcooled branch refrigerant flows from the supercooling heat exchanger (71). The flow path switching means (78) communicates the downstream side passage (74b) with the suction side of the first compressor (21a) in the first state, and the downstream side passage (74b) in the second state. And the suction side of the second compressor (21b).

    In the above invention, after the refrigerant branching from the liquid pipe (P1) to the upstream passage (74a) is depressurized by the expansion mechanism (75), the liquid refrigerant is supercooled by the supercooling heat exchanger (71). It evaporates and flows to the downstream passage (74b). The evaporated refrigerant flows to the suction side of the first compressor (21a) when the flow path switching means (78) switches to the first state, and the flow path switching means (78) switches to the second state. And flows to the suction side of the second compressor (21b).

    In a third aspect based on the second aspect, the second utilization system includes a utilization side heat exchanger (41), and is a liquid refrigerant that flows from the liquid pipe (P1) to the second utilization system. The 3rd utilization system which a part branches is connected. And the said 3rd utilization system | strain is equipped with the auxiliary compressor (61) of the low stage side for compressing a refrigerant | coolant 2 steps | paragraphs by making the 2nd compressor (21b) of a heat source system into a high stage side.

    In the above invention, the gas refrigerant evaporated in the use side heat exchanger (51) is compressed in two stages by the auxiliary compressor (61) with the compressors (21a, 21b) of the heat source system. That is, the said 3rd utilization system | strain comprises the freezer etc. which a refrigerant | coolant evaporates at the temperature lower than the evaporation temperature of the refrigerant | coolant in a 1st utilization system and a 2nd utilization system | strain.

    According to a fourth invention, in the third invention, the supercooling heat exchanger (71) and the supercooling passage (74) are housed in a casing to constitute a supercooling unit (1F).

    In the above invention, since the supercooling heat exchanger (71) and the like are unitized, the space of the apparatus can be saved. In addition, a supercooling unit (1F) can be easily installed later on an existing device.

    Further, in a fifth aspect based on the fourth aspect, the refrigerant discharged from the auxiliary compressor (61) flows toward the suction side of the second compressor (21b) in the supercooling unit (1F). A hot gas pipe (67) passes.

    In the above-described invention, the inside of the supercooling unit (1F) is shut off from the outside by the casing, and the heat in and out is suppressed. Thereby, in the supercooling unit (1F), for example, the temperature of the ambient air of the supercooling heat exchanger (71) or the like extremely decreases, and frost is easily generated in the supercooling heat exchanger (71) or the like. . However, in the present invention, in the supercooling unit (1F), the high-temperature discharged refrigerant dissipates heat through the hot gas pipe (67), and the ambient air such as the supercooling heat exchanger (71) is heated. Therefore, generation and growth of frost in the supercooling heat exchanger (71) and the like are suppressed without providing a separate heating means such as an electric heater in the supercooling unit (1F).

    The sixth invention is the first or second use system according to the first or second invention, based on the temperature of the air that exchanges heat with the refrigerant in the use side heat exchanger (31, 51). Control means (80) for judging the load state of the system and switching the flow path switching means (78) between the first state and the second state in accordance with the load state of each utilization system.

    In the above invention, the control means (80) determines the cooling load state of each utilization system based on the temperature of the air sucked into the utilization side heat exchanger (31, 51). For example, if the difference between the air temperature sucked into the use side heat exchanger (31, 51) and its set temperature is higher than a predetermined value, the cooling load of the use system is determined to be large and lower than a predetermined value. Therefore, it is determined that the cooling load of the utilization system is small.

    For example, when it is determined that the cooling load of the first usage system is large and the cooling load of the second usage system is small, the flow path switching unit (78) is brought into the second state by the control unit (60). Can be switched. When it is determined that the cooling load of the first usage system is small and the cooling load of the second usage system is determined to be large, the flow path switching unit (78) is switched to the first state by the control unit (60). .

    According to a seventh invention, in the first or second invention, the first usage system and the second usage system are based on the suction pressures of the first compressor (21a) and the second compressor (21b). Control means (80) for judging the load state and switching the flow path switching means (78) between the first state and the second state according to the load state of each utilization system is provided.

    In the above invention, the control means (80) determines the cooling load state of the use system based on the suction pressure of each compressor (21a, 21b), that is, the low pressure of the refrigerant in each use system. For example, if the suction pressure of each compressor (21a, 21b) is lower than a predetermined value, it is determined that the cooling load of the utilization system is small.

    For example, when it is determined that the cooling load of the first usage system is not small and the cooling load of the second usage system is determined to be small, the flow path switching unit (78) is in the second state by the control unit (60). Can be switched to. When it is determined that the cooling load of the first usage system is small and the cooling load of the second usage system is not small, the flow switching means (78) is switched to the first state by the control means (60). It is done.

    Therefore, according to the present invention, the first refrigerant (21a) and the second compressor that mainly take charge of the branched refrigerant after supercooling the liquid refrigerant and the branched refrigerant after the liquid refrigerant is supercooled are branched. Since the compressor (21b) is switched to be sucked, the circulation amount of the supercooled liquid refrigerant is increased for the utilization system with a large load, and the circulation amount is reduced by that amount. The branched refrigerant after being supercooled to (21a, 21b) can be returned. Thereby, the cooling capacity can be adjusted according to the magnitude relationship of the load of each utilization system without breaking the balance between the discharge amount and the suction amount in the compressor (21a, 21b). Therefore, the operating efficiency can be improved while protecting the compressors (21a, 21b).

    In particular, according to the second invention, the downstream side passage (74b) of the supercooling passage (74) is connected to the suction side of the first compressor (21a) and the second compressor by switching the flow passage switching means (78). Since it is made to communicate with either of the suction sides of (21b), the branched refrigerant after supercooling can be reliably returned to the predetermined compressor (21a, 21b).

    Moreover, according to the third aspect of the invention, also in the refrigeration apparatus including the third usage system including the auxiliary compressor (61) for compressing the refrigerant in two stages, the cooling of the first usage system and the second usage system is performed. Capability can be adjusted according to the magnitude of load.

    Furthermore, according to the fourth invention, the supercooling heat exchanger (71) and the supercooling passage (74) are unitized and provided in the liquid pipe (P1). It can be easily installed later. In addition, since no electrical equipment or the like is provided, work such as electrical wiring is not required, and installation can be performed more easily.

    According to the fifth aspect of the invention, the hot gas pipe (67) through which the refrigerant discharged from the auxiliary compressor (61) flows passes through the supercooling unit (1F), so that the supercooling heat exchanger (71) The surrounding air can be heated. Thereby, generation | occurrence | production and growth of frost in a supercooling unit (1F) can be suppressed, without providing an electric heater etc. separately.

    According to the sixth or seventh invention, the load state of each utilization system is determined based on the intake air temperature of the utilization side heat exchanger (31, 51) or the intake pressure of each compressor (21a, 21b). Since it was made to do, the magnitude relationship of the load of each utilization system | strain can be judged reliably. Therefore, the flow path switching means (78) can be switched appropriately, and the discharge amount and the suction amount in the compressor (21a, 21b) can be reliably balanced.

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

    The refrigeration apparatus of this embodiment is installed in a convenience store or the like, and performs air conditioning in the store and cooling in the showcase. As shown in FIG. 1, the refrigeration apparatus (1) includes an outdoor unit (1A), a refrigerated showcase (1B), a refrigeration showcase (1C), an air conditioning unit (1D), and a booster unit (1E). And a supercooling unit (1F). In the refrigeration apparatus (1), the refrigerant circuit (10) is configured by connecting the remaining refrigerated showcase (1B) and the like to the outdoor unit (1A) by piping. The refrigerant circuit (10) is configured to perform a vapor compression refrigeration cycle by circulating the refrigerant.

<Outdoor unit>
The outdoor unit (1A) includes two compressors (21a, 21b), a four-way switching valve (22) as a flow path switching means, and an outdoor heat exchanger (23) as a heat source side heat exchanger. It has. The compressors (21a, 21b), the four-way switching valve (22), and the outdoor heat exchanger (23) constitute a heat source system.

    The two compressors (21a, 21b) are a fixed capacity compressor (21a) and a variable capacity compressor (21b), both of which are constituted by a hermetic high-pressure dome type scroll compressor. The fixed capacity compressor (21a) is a compressor whose electric motor is always driven at a constant rotational speed and whose capacity cannot be changed. On the other hand, the variable capacity compressor (21b) is a compressor whose capacity is variable stepwise or continuously by inverter control of the electric motor. The two compressors (21a, 21b) constitute a compression mechanism (2A) of the outdoor unit (1A). The fixed capacity compressor (21a) mainly constitutes a first compressor for a first usage system, which will be described later, and the variable capacity compressor (21b) mainly serves as a second compression for a second usage system, which will be described later. Make up machine.

    The discharge sides of the two compressors (21a, 21b) are connected to a common discharge pipe (11), and the discharge pipe (11) is connected to one port of the four-way switching valve (22). . The one end of the four-way selector valve (22) is connected to the gas side end, which is one end of the outdoor heat exchanger (23), via the first outdoor gas pipe (12), and the outdoor heat exchanger The liquid side end which is the other end of (23) is connected to one end of the outdoor liquid pipe (13) which is a liquid line. The other end of the outdoor liquid pipe (13) passes through the receiver (24) and then extends to the outside of the outdoor unit (1A) via the closing valve (28) and is connected to the communication liquid pipe (P1). .

    The suction side of the fixed capacity compressor (21a) is connected to one port of the four-way switching valve (22) via the first low-pressure gas pipe (15). One end of the second low-pressure gas pipe (18) is connected to the suction side of the variable capacity compressor (21b), and the other end of the second low-pressure gas pipe (18) is connected to the outdoor unit via the closing valve (28). It is extended to the outside of (1A) and connected to the first communication gas pipe (P4). One end of the second outdoor gas pipe (14) is connected to one port of the four-way switching valve (22), and the other end of the second outdoor gas pipe (14) is connected to the closing valve (28). And extended to the outside of the outdoor unit (1A) and connected to the second communication gas pipe (P5). That is, in the fixed capacity compressor (21a) and the variable capacity compressor (21b), the refrigerant is merged on the discharge side, but the refrigerant is individually sucked on the suction side without being merged.

    The outdoor heat exchanger (23) is, for example, a cross-fin type fin-and-tube heat exchanger, and the outdoor fan (25) and the outside air temperature sensor (26) are arranged close to each other. The outdoor air temperature sensor (26) constitutes temperature detecting means for detecting the temperature of outdoor air sucked by the outdoor fan (25). The outdoor heat exchanger (23) is configured to exchange heat between the refrigerant and the outdoor air.

    In the four-way switching valve (22), the discharge pipe (11) and the first outdoor gas pipe (12) communicate with each other, and the second outdoor gas pipe (14) and the first low-pressure gas pipe (15) communicate with each other. The first state (indicated by the solid line in FIG. 1), the discharge pipe (11) and the second outdoor gas pipe (14) communicate with each other, and the first outdoor gas pipe (12) and the first low-pressure gas pipe (15). Are switched to a second state (a state indicated by a broken line in FIG. 1).

    The outdoor liquid pipe (13) includes an auxiliary liquid pipe (16) having an outdoor expansion valve (27) as an expansion mechanism and bypassing the receiver (24). In addition, a check valve that allows only the flow of refrigerant toward the receiver (24) is provided between the connection portion of the auxiliary liquid pipe (16) in the outdoor liquid pipe (13) and the upstream side of the receiver (24). CV1) is provided. Furthermore, the outdoor liquid pipe (13) is provided with a branch liquid pipe (17). One end of the branch liquid pipe (17) is connected between the check valve (CV1) and the receiver (24), and the other end is connected between the downstream side of the receiver (24) and the closing valve (28). It is connected. The branch liquid pipe (17) is provided with a check valve (CV2) that allows only a refrigerant flow from the closing valve (28) side toward the receiver (24).

    The low pressure gas pipes (15, 18) of the fixed capacity compressor (21a) and the variable capacity compressor (21b) include a first pressure sensor which is a pressure detection means for the refrigerant sucked in the compressors (21a, 21b). (19a) and a second pressure sensor (19b) are provided. That is, the first pressure sensor (19a) detects the low pressure of the refrigerant in the first usage system, and the second pressure sensor (19b) detects the low pressure of the refrigerant in the second usage system.

<Air conditioning unit>
The air conditioning unit (1D) constitutes an air conditioning system that performs air conditioning by heating and cooling the inside of the store. Specifically, this air conditioning unit (1D) includes an air conditioning heat exchanger (51) that is a use side heat exchanger and an air conditioning expansion valve (52) that is an expansion mechanism. As this air conditioning expansion valve (52), for example, an electronic expansion valve is used. The liquid side end, which is one end of the air conditioning heat exchanger (51), is extended to the outside of the air conditioning unit (1D) via the air conditioning expansion valve (52) and connected to the first branch liquid pipe (P2). Yes. On the other hand, the gas side end which is the other end of the air conditioning heat exchanger (51) is extended to the outside of the air conditioning unit (1D) and connected to the second communication gas pipe (P5). The first branch liquid pipe (P2) is a liquid pipe branched from the middle of the connecting liquid pipe (P1).

    The air conditioning heat exchanger (51) is, for example, a cross fin type fin-and-tube heat exchanger, and the air conditioning fan (55) and the room temperature sensor (56) are arranged close to each other. The room temperature sensor (56) constitutes temperature detection means for detecting the temperature of the indoor air (in-store air) sucked by the air conditioning fan (55). The air conditioning heat exchanger (51) is provided with an air conditioning heat exchange sensor (53) as temperature detecting means for detecting an evaporation temperature or a condensation temperature, which is a refrigerant temperature in the air conditioning heat exchanger (51). A gas temperature sensor (54) is provided on the gas side as temperature detecting means for detecting the temperature of the gas refrigerant. And the said air-conditioning heat exchanger (51) is comprised so that a refrigerant | coolant and room air may heat-exchange.

<Refrigerated showcase>
The refrigerated showcase (1B) constitutes a cooling system that refrigerates food and the like. Specifically, the refrigerated showcase (1B) includes a refrigerated heat exchanger (31) that is a use-side heat exchanger and a refrigerated expansion valve (32) that is an expansion mechanism. For example, an electronic expansion valve is used for the refrigeration expansion valve (32). The liquid side end, which is one end of the refrigeration heat exchanger (31), is extended to the outside of the refrigeration showcase (1B) via the refrigeration expansion valve (32) and connected to the communication liquid pipe (P1). . On the other hand, the gas side end which is the other end of the refrigeration heat exchanger (31) is extended to the outside of the refrigeration showcase (1B) and connected to the first communication gas pipe (P4).

    The refrigeration heat exchanger (31) is, for example, a cross-fin type fin-and-tube heat exchanger, and a refrigeration fan (35) and a refrigeration temperature sensor (36) are arranged close to each other. The said refrigeration temperature sensor (36) comprises the temperature detection means which detects the temperature of the air in a showcase (air in a store | warehouse | chamber) inhaled by the refrigeration fan (35). The refrigeration heat exchanger (31) is provided with a refrigeration heat exchange sensor (33) as temperature detection means for detecting the evaporation temperature, which is the refrigerant temperature in the refrigeration heat exchanger (31), and the gas side A gas temperature sensor (34) is provided as temperature detecting means for detecting the temperature of the gas refrigerant. The refrigeration heat exchanger (31) is configured to exchange heat between the refrigerant and the showcase air.

<Frozen showcase>
The freezing showcase (1C) constitutes a cooling system for freezing food and the like. Specifically, the refrigeration showcase (1C) includes a refrigeration heat exchanger (41) that is a use-side heat exchanger and a refrigeration expansion valve (42) that is an expansion mechanism. For example, an electronic expansion valve is used as the refrigeration expansion valve (42). The liquid side end, which is one end of the refrigeration heat exchanger (41), is extended to the outside of the refrigeration showcase (1C) via the refrigeration expansion valve (42) and connected to the second branch liquid pipe (P3). ing. The second branch liquid pipe (P3) is a liquid pipe branched from the middle of the communication liquid pipe (P1). A gas-side end, which is the other end of the refrigeration heat exchanger (41), is connected to a connecting gas pipe (62) that connects the refrigeration showcase (1C) and the booster unit (1E).

    The refrigeration heat exchanger (41) is, for example, a cross fin type fin-and-tube heat exchanger, and a refrigeration fan (45) and a refrigeration temperature sensor (46) are arranged close to each other. The refrigeration temperature sensor (46) constitutes temperature detection means for detecting the temperature of the air in the showcase (inside air) sucked by the refrigeration fan (45). The refrigeration heat exchanger (41) is provided with a refrigeration heat exchange sensor (43) as temperature detection means for detecting the evaporation temperature, which is the refrigerant temperature in the refrigeration heat exchanger (41), and the gas side Is provided with a gas temperature sensor (44). The refrigeration heat exchanger (41) is configured to exchange heat between the refrigerant and the showcase air.

    In the refrigeration apparatus (1) of the present embodiment, the communication liquid pipe (P1), the first branch liquid pipe (P2), and the second branch liquid pipe (P3) constitute a liquid pipe, and the first communication gas pipe ( P4) and the second communication gas pipe (P5) constitute a gas pipe.

<Booster unit>
The booster unit (1E) includes a booster compressor (61) as an auxiliary compressor of the variable capacity compressor (21b) in the outdoor unit (1A). A connection gas pipe (62) extending from the refrigeration showcase (1C) is connected to the suction side of the booster compressor (61) as a suction pipe, and a discharge pipe (64) is connected to the discharge side. The discharge pipe (64) is provided with an oil separator (63) and a check valve (CV4) in order from the booster compressor (61) side. An oil return pipe (65) having a capillary tube (CP) as an expansion mechanism is connected between the oil separator (63) and the connection gas pipe (62).

    The booster compressor (61) is composed of a hermetic high-pressure dome type swing compressor. The booster compressor (61) is a compressor whose capacity is variable stepwise or continuously by inverter control of the electric motor. The booster compressor (61) is configured such that the refrigerant evaporation temperature in the refrigeration heat exchanger (41) of the refrigeration showcase (1C) is equal to the refrigerant evaporation temperature in the refrigeration heat exchanger (31) of the refrigeration showcase (1B). The refrigerant is compressed in two stages with the variable capacity compressor (21b) of the outdoor unit (1A) so as to be lower. That is, the booster compressor (61) constitutes a low stage compressor, and the variable capacity compressor (21b) of the outdoor unit (1A) constitutes a high stage compressor.

    The booster unit (1E) is provided with a bypass pipe (66) connected between the connection gas pipe (62) and the discharge pipe (64). One end of the bypass pipe (66) is connected to the upstream side of the connection part of the oil return pipe (65) in the connection gas pipe (62), and the other end is downstream of the check valve (CV4) in the discharge pipe (64). Connected to the side. The bypass pipe (66) allows the refrigerant in the connecting gas pipe (62) to bypass the booster compressor (61) and the oil separator (63) when the booster compressor (61) is stopped or the like is stopped. ). The bypass pipe (66) is provided with a check valve (CV5) that allows only the flow of refrigerant from the connecting gas pipe (62) toward the discharge pipe (64).

    In the refrigeration apparatus (1) of the present embodiment, the air conditioning unit (1D) constitutes the first usage system, the refrigerated showcase (1B) constitutes the second usage system, the refrigeration showcase (1C) and the booster unit (1E) constitutes the third usage system.

<Supercooling unit>
The supercooling unit (1F) is provided on the outdoor unit (1A) side from the connection of the first branch liquid pipe (P2) and the second branch liquid pipe (P3) in the middle of the communication liquid pipe (P1). . The supercooling unit (1F) includes a supercooling heat exchanger (71) and a supercooling passage (74).

  The supercooling heat exchanger (71) is a so-called plate heat exchanger, and a plurality of first flow paths (72) and a plurality of second flow paths (73) are formed therein. The supercooling heat exchanger (71) has a first flow path (72) connected to the connecting liquid pipe (P1) and a second flow path (73) connected to the supercooling path (74).

    The supercooling passage (74) includes an upstream passage (74a) and a downstream passage (74b). The upstream side passage (74a) branches from the refrigeration showcase (1B) side from the first flow path (72) in the communication liquid pipe (P1) and is connected to the inlet side end of the second flow path (73). ing. The upstream passage (74a) is provided with a supercooling expansion valve (75) constituted by a temperature automatic expansion valve as an expansion mechanism. The downstream passage (74b) has one end connected to the outlet side end of the second flow path (73) and the other end extending from the supercooling unit (1F) into the outdoor unit (1A). . And the temperature sensing cylinder (76) of the said supercooling expansion valve (75) is attached to the 2nd flow path (73) side of this downstream channel | path (74b).

    That is, in the supercooling heat exchanger (71), the branched refrigerant branched from the communication liquid pipe (P1) to the upstream side passage (74a) flows to the second flow path (73) of the supercooling heat exchanger (71). The liquid refrigerant in the first flow path (72) is supercooled and evaporated, while the supercooled liquid refrigerant flows to the refrigerated showcase (1B), the freezer showcase (1B), and the air conditioning unit (1D). It is configured.

    Further, as a feature of the present invention, the outdoor unit (1A) is provided with a three-way switching valve (78) which is a channel switching means.

    The other end of the downstream passage (74b) of the supercooling passage (74) extended from the supercooling unit (1F) is connected to one port of the three-way switching valve (78). A first connection gas pipe (77) connected to the middle of the second low-pressure gas pipe (18) is connected to one port of the three-way switching valve (78), and a second port is connected to the remaining one port. A second connection gas pipe (79) connected to the middle of the outdoor gas pipe (14) is connected.

    The three-way switching valve (78) is in a first state in which the downstream passage (74b) communicates with the second connection gas pipe (79) and is disconnected from the first connection gas pipe (77) (broken line in FIG. 1). And a second state in which the downstream passage (74b) communicates with the first connection gas pipe (77) and is disconnected from the second connection gas pipe (79) (a state indicated by a solid line in FIG. 1). It is comprised so that it may switch to. That is, when the three-way switching valve (78) is in the first state, the branched refrigerant in the downstream passage (74b) flows to the suction side of the fixed capacity compressor (21a), and in the second state, the downstream passage ( The branch refrigerant of 74b) flows to the suction side of the variable capacity compressor (21b).

    Further, a hot gas pipe (67) through which the refrigerant discharged from the booster compressor (61) flows toward the suction side of the variable capacity compressor (21b) passes through the supercooling unit (1F). One end of the hot gas pipe (67) is connected to the discharge pipe (64) of the booster compressor (61), the other end is connected to the middle of the first connection gas pipe (77), and the middle is connected to the supercooling unit (1F). ) Pass through a predetermined location. That is, the hot gas pipe (67) constitutes a heating means for radiating the high-temperature heat of the discharged refrigerant and heating the ambient air.

    The piping path of the hot gas pipe (67) in the supercooling unit (1F) will be described in detail with reference to FIG. The supercooling unit (1F) includes a rectangular casing (70). In FIG. 2, the right side surface of the casing (70) represents the front surface and the left side surface represents the back surface, and “right” and “left”, which are expressed below, indicate directions viewed from the front side.

    The communication liquid pipe (P1) extends from the lower right side of the front plate into the casing (70) and again passes through the first flow path (72) in the supercooling heat exchanger (71) to lower the lower right side of the front plate. To the outside. The upstream-side passage (74a) of the supercooling passage (74) is disposed at a substantially central bottom portion in the casing (70), and the downstream-side passage (74b) is disposed at a substantially central upper portion in the casing (70). Has been. In addition, a drain discharge port (DR) for discharging condensed water generated in the casing (70) to the outside is provided at the center bottom portion of the casing (70).

    The hot gas pipe (67) extends from the upper right of the front plate into the casing (70), then extends from the right side to the left along the substantially central bottom in the casing (70), and then the supercooling heat exchanger (71 ) Is arranged so as to pass around the lower part. That is, the hot gas pipe (67) passes in the vicinity of the upstream passage (74a) of the supercooling passage (74) and simultaneously in the vicinity of the drain outlet (DR), and then the supercooling heat exchanger (71 ).

    The refrigeration apparatus (1) includes a controller (80). The controller (80) is configured to control the three-way switching valve (78), the four-way switching valve (22), the various expansion valves (27, 52,...), And the like.

    The controller (80) receives the detected temperatures (air temperature T) of the room temperature sensor (56), the refrigeration temperature sensor (36), and the refrigeration temperature sensor (46). Based on the input air temperature T, the controller (80) determines the magnitude of the air conditioning load of the air conditioning unit (1D), the refrigeration load of the refrigerated showcase (1B), and the refrigeration load of the refrigerated showcase (1C). Judgment is made and switching control of the three-way switching valve (78) is performed.

    Specifically, the controller (80) is configured so that the temperature difference between the air temperature T and the target temperature Ta is preset at the time of operation of each compressor (21a, 21b) (in this embodiment, 5). If it is higher than (° C.), it is judged that the load is large. In addition, the controller (80) is a lower limit value (1 ° C. in the present embodiment) in which the temperature difference between the air temperature T and the target temperature Ta is set in advance during operation of each compressor (21a, 21b). If it is lower than that, it is determined that the load is small.

    When the controller (80) determines that the air conditioning load is large and determines that at least one of the refrigeration load and the refrigeration load is small, the controller switches the three-way switching valve (78) to the second state. . The controller (80) determines that at least one of the refrigeration load and the refrigeration load is large, and switches the three-way switching valve (78) to the first state when determining that the air conditioning load is small. .

    On the other hand, when it is determined that all of the air conditioning load, the refrigeration load, and the refrigeration load are large, or both are small, or neither is large or small, the controller (80) determines whether the three are based on the priority setting. Switch the path selector valve (78). In the priority setting, if the air conditioning load is in the above-described load state, the air conditioning unit (1D) is given priority to increase its capacity, or the refrigerated showcase (1B) and the refrigerated showcase (1C) are given priority. Whether to increase capacity is set by the user before driving. For example, when priority is given to the air conditioning unit (1D), the controller (80) switches the three-way switching valve (78) to the second state. When priority is given to the refrigerated showcase (1B) and the refrigerated showcase (1C), the controller (80) switches the three-way switching valve (78) to the first state.

-Driving action-
Next, the operation of the refrigeration apparatus (1) described above will be described. In the refrigeration apparatus (1), the refrigerant is condensed in the outdoor heat exchanger (23), and the refrigerant is evaporated in the refrigeration heat exchanger (31), the refrigeration heat exchanger (41), and the air conditioning heat exchanger (51). The first and second cooling / freezing operations, the first heating / freezing operation in which the refrigerant is condensed in the air-conditioning heat exchanger (51), and the refrigerant is evaporated in the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41); The refrigerant is condensed in the heat exchanger (51) and can be switched to the second heating / refrigeration operation in which the refrigerant evaporates in the outdoor heat exchanger (23), the refrigeration heat exchanger (31), and the refrigeration heat exchanger (41). It is configured.

<First cooling / freezing operation>
In this first cooling / freezing operation, the air in the store is cooled by the air conditioning unit (1D), and at the same time, the air in the refrigerator is cooled in the refrigerated showcase (1B) and the freezer showcase (1C). is there. In this operation, the controller (80) determines that the cooling load (air conditioning load) of the air conditioning unit (1D) is large, and at least the refrigeration load of the refrigerated showcase (1B) and the refrigeration load of the refrigerated showcase (1C) This is performed when it is determined that one is small. This operation is also performed when the controller (80) prioritizes the air conditioning unit (1D).

    As shown in FIG. 3, the controller (80) causes the four-way selector valve (22) to be in the first state, the outdoor expansion valve (27) to be in the fully closed state, the air conditioning expansion valve (52), the refrigeration expansion valve ( 32) The refrigeration expansion valve (42) and the supercooling expansion valve (75) are each set to a predetermined opening degree. Then, the three-way switching valve (78) is set to the second state. In this state, the fixed capacity compressor (21a), the variable capacity compressor (21b), and the booster compressor (61) are driven.

    The gas refrigerant discharged from the fixed capacity compressor (21a) and the variable capacity compressor (21b) merges in the discharge pipe (11) and passes through the first outdoor gas pipe (12) from the four-way switching valve (22). After that, it flows into the outdoor heat exchanger (23) and is condensed by exchanging heat with the outdoor air taken in by the outdoor fan (25). The condensed liquid refrigerant flows through the outdoor liquid pipe (13), and then flows through the receiver (24) to the communication liquid pipe (P1).

    The liquid refrigerant that has flowed to the communication liquid pipe (P1) flows to the supercooling unit (1F). In this supercooling unit (1F), after the branched refrigerant branched from the liquid refrigerant in the communication liquid pipe (P1) to the upstream passage (74a) is depressurized by the supercooling expansion valve (75), the supercooling heat exchanger ( 71) to the second flow path (73). In this supercooling heat exchanger (71), the branched refrigerant in the second flow path (73) evaporates by exchanging heat with the liquid refrigerant flowing in the first flow path (72), and the liquid in the first flow path (72). The refrigerant is supercooled. This supercooled liquid refrigerant flows through the connecting liquid pipe (P1), partly through the first branch liquid pipe (P2) to the air conditioning unit (1D), and partly through the second branch liquid pipe (P3). ) To the freezer showcase (1C) and the rest to the refrigerated showcase (1B).

    In the air conditioning unit (1D), the supercooled liquid refrigerant is decompressed by the air conditioning expansion valve (52), then flows to the air conditioning heat exchanger (51), and the store air sucked by the air conditioning fan (55). Heat exchanges and evaporates, and the store air is cooled. The evaporated gas refrigerant returns to the outdoor unit (1A) through the second communication gas pipe (P5), and is supplied to the second outdoor gas pipe (14), the four-way switching valve (22), and the first low-pressure gas pipe (15 ) Through the fixed capacity compressor (21a) in order.

    In the refrigerated showcase (1B), the supercooled liquid refrigerant is decompressed by the refrigeration expansion valve (32), then flows into the refrigeration heat exchanger (31), and is sucked by the refrigeration fan (35). Heat is exchanged with the air to evaporate, and the air in the cabinet is cooled. The evaporated gas refrigerant returns to the outdoor unit (1A) through the first communication gas pipe (P4), and is again sucked into the variable capacity compressor (21b) from the second low-pressure gas pipe (18).

    In the refrigeration showcase (1C), the supercooled liquid refrigerant is decompressed by the refrigeration expansion valve (42), then flows to the refrigeration heat exchanger (41), and is sucked by the refrigeration fan (45). Heat is exchanged with the air to evaporate, and the air in the cabinet is cooled. The evaporated gas refrigerant is sucked into the booster compressor (61) and compressed, then returns to the outdoor unit (1A) through the hot gas pipe (67), and passes through the first connecting gas pipe (77). It flows to the second low-pressure gas pipe (18). Then, this gas refrigerant merges with the refrigerant from the refrigerated showcase (1B) in the second low-pressure gas pipe (18), and is sucked again into the variable capacity compressor (21b).

    In the supercooling unit (1D), the discharge refrigerant flowing through the hot gas pipe (67) dissipates heat, so that the air around the hot gas pipe (67) is heated. That is, the air around the upstream passage (74a) through which the hot gas pipe (67) passes, the drain outlet (DR), and the supercooling heat exchanger (71) is heated. Therefore, generation | occurrence | production and growth of frost in the said supercooling heat exchanger (71) etc. can be suppressed. And since it heats from the upstream channel | path (74a) with low ambient temperature, generation | occurrence | production of frost etc. can be suppressed reliably and efficiently.

    On the other hand, the branched refrigerant evaporated in the supercooling heat exchanger (71) returns to the outdoor unit (1A) through the downstream passage (74b), and passes from the three-way switching valve (78) to the first connecting gas pipe (77 ) To the second low-pressure gas pipe (18). And this branch refrigerant | coolant returns to a variable capacity compressor (21b) with the refrigerant | coolant which flowed from the refrigerated showcase (1B) and the booster compressor (61).

    Next, the cooling capacity exhibited in the refrigerated showcase (1B), the freezer showcase (1C), and the air conditioning unit (1D) will be described.

    First, the liquid refrigerant flowing through each of the refrigerated showcase (1B), the refrigerated showcase (1C), and the air conditioning unit (1D) increases as the amount of heat is supercooled. In the refrigeration showcase (1C) and the air conditioning unit (1D), the refrigeration expansion valve (42) and the air conditioning expansion so that the refrigerant circulation amount is almost the same as that before the supercooling unit (1F) is provided. If the opening degree of the valve (52) is set, the cooling capacity and the cooling capacity will be increased by the increased amount of heat of the refrigerant. On the other hand, in the refrigerated showcase (1B), the refrigerant circulation amount is reduced by the flow rate of the branch refrigerant used in the supercooling heat exchanger (71), so that the cooling capacity is lowered. In this way, while improving the cooling capacity of the refrigeration showcase (1C), the capacity is adjusted according to the cooling load of the air conditioning unit (1D) and the cooling load of the refrigerated showcase (1B). Therefore, an operation without waste in capacity is performed.

    Here, although the amount of refrigerant supplied to the refrigerated showcase (1B) and refrigeration showcase (1C), which are cooling systems, decreases, the refrigerant that has evaporated in the supercooling heat exchanger (71) is cooled as described above. Since the variable capacity compressor (21b) is returned to the system, the suction pressure (low pressure) of the variable capacity compressor (21b) can be prevented from extremely decreasing. Therefore, the variable capacity compressor (21b) can be protected.

<Second cooling / freezing operation>
In the second cooling / freezing operation, as in the first cooling / freezing operation described above, the interior air is cooled at the same time as the inside of the store is cooled. In this operation, the controller (80) determines that the cooling load (air conditioning load) of the air conditioning unit (1D) is small, and at least the refrigeration load of the refrigerated showcase (1B) and the refrigeration load of the refrigerated showcase (1C) This is performed when it is determined that one is larger. This operation is also performed when the controller (80) gives priority to the refrigerated showcase (1B) and the refrigerated showcase (1C). Here, settings and operations different from the first cooling / freezing operation will be described.

    As shown in FIG. 4, the three-way selector valve (78) is set to the first state by the controller (80). In this state, the branched refrigerant evaporated in the supercooling heat exchanger (71) returns to the outdoor unit (1A) through the downstream side passage (74b), and passes from the three-way switching valve (78) to the second connection gas pipe (79 ) To the second outdoor gas pipe (14). The branched refrigerant is sucked into the fixed capacity compressor (21a) together with the refrigerant of the air conditioning unit (1D).

    Also in this operation, the liquid refrigerant flowing in each of the refrigerated showcase (1B), the refrigerated showcase (1C), and the air conditioning unit (1D) increases as the amount of heat is supercooled. In the refrigerated showcase (1B) and the refrigerated showcase (1C), the refrigeration expansion valve (32) and the refrigeration are provided so that the refrigerant circulation amount is almost the same as before the supercooling unit (1F) is provided. If the opening degree of the expansion valve (42) is set, the cooling capacity will increase by the amount of heat increased by the refrigerant. On the other hand, in the air conditioning unit (1D), the refrigerant circulation amount is reduced by the amount of the branch refrigerant used in the supercooling heat exchanger (71), so that the cooling capacity is reduced depending on the cooling load. Become. In this way, while improving the cooling capacity of the refrigeration showcase (1C), the capacity is adjusted according to the cooling load of the air conditioning unit (1D) and the cooling load of the refrigerated showcase (1B).

    Here, the amount of refrigerant supplied to the air conditioning unit (1D) that is the air conditioning system is reduced, but the branched refrigerant evaporated in the supercooling heat exchanger (71) is returned to the fixed capacity compressor (21a) of the air conditioning system. As a result, the suction pressure (low pressure) of the fixed capacity compressor (21a) can be prevented from extremely decreasing. Therefore, the fixed capacity compressor (21a) can be protected.

<First heating / freezing operation>
This first heating and refrigeration operation heats the interior air by heating the indoor air with the air conditioning unit (1D) and at the same time cools the air in the refrigerator in the refrigerated showcase (1B) and the refrigerated showcase (1C). is there.

    As shown in FIG. 5, the four-way switching valve (22) is set to the second state by the controller (80), the refrigeration expansion valve (32) and the refrigeration expansion valve (42) are set to a predetermined opening degree, and the air conditioning expansion is performed. Each of the valves (52) is set to a fully open state. Further, the outdoor expansion valve (27) and the supercooling expansion valve (75) are set in the fully closed state, and the three-way switching valve (78) is set in the second state. In this state, the variable capacity compressor (21b) and the booster compressor (61) are driven, and the fixed capacity compressor (21a) is stopped.

    The gas refrigerant discharged from the variable capacity compressor (21b) sequentially passes through the discharge pipe (11), the four-way switching valve (22), the second outdoor gas pipe (14), and the second communication gas pipe (P5). To the air conditioning unit (1D). In this air conditioning unit (1D), the gas refrigerant is condensed by exchanging heat with the store air taken in by the air conditioning fan (55) in the air conditioning heat exchanger (51), and the store air is heated. The condensed liquid refrigerant flows to the connecting liquid pipe (P1) through the first branch liquid pipe (P2), partly flows to the refrigeration showcase (1C) through the second branch liquid pipe (P3), and the rest is refrigerated. Flows to case (1B). It should be noted that the refrigerant amount corresponding to the suction amount of the booster compressor (61) flows preferentially to the refrigeration showcase (1C).

    In the refrigerated showcase (1B) and the freezer showcase (1C), the internal air is cooled in the same manner as in the above-described cooling and freezing operation. After the gas refrigerant evaporated in the refrigeration heat exchanger (31) flows to the first communication gas pipe (P4), the gas refrigerant evaporated in the refrigeration heat exchanger (41) is compressed by the booster compressor (61) , Flows through the hot gas pipe (67) and the first connection gas pipe (77) to the first communication gas pipe (P4). The refrigerant in the first communication gas pipe (P4) is again drawn into the variable capacity compressor (21b) from the second low-pressure gas pipe (18).

    Thus, in the first heating and refrigeration operation, the refrigerant absorbs heat in the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41), and the refrigerant radiates heat in the air conditioning heat exchanger (51). That is, the inside of the store is heated using the heat that the refrigerant has absorbed from the air in the refrigerator in the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41).

    This operation is mainly performed in winter when the cooling load is relatively small, so even if the liquid refrigerant is not supercooled by the supercooling unit (1F), the refrigerated showcase (1B) and refrigeration showcase (1C The required cooling capacity is obtained in

<Second heating and freezing operation>
The second heating / freezing operation is an operation for heating the inside of the store similarly to the above-described first heating / freezing operation, and is performed when the heating capacity is insufficient in the first heating / freezing operation.

    As shown in FIG. 6, the controller (80) sets the four-way switching valve (22) to the second state, and the outdoor expansion valve (27), the refrigeration expansion valve (32), and the refrigeration expansion valve (42) The air conditioning expansion valve (52) is set to a fully open state at a predetermined opening degree. Further, the supercooling expansion valve (75) is set to the fully closed state, and the three-way switching valve (78) is set to the second state. In this state, the fixed capacity compressor (21a), the variable capacity compressor (21b), and the booster compressor (61) are driven.

    The gas refrigerant discharged from the fixed capacity compressor (21a) and the variable capacity compressor (21b) merges in the discharge pipe (11), and the four-way switching valve (22), the second outdoor gas pipe (14), and It flows to the air conditioning unit (1D) through the second communication gas pipe (P5) in order. In this air conditioning unit (1D), the gas refrigerant is condensed by exchanging heat with the store air as in the first heating and refrigeration operation described above, and the store air is heated. This condensed liquid refrigerant flows to the connecting liquid pipe (P1) through the first branch liquid pipe (P2), a part of which is distributed to the refrigerated showcase (1B) and the refrigerated showcase (1C), and the rest is supercooled. It flows to the supercooling heat exchanger (71) of the unit (1F).

    In the refrigerated showcase (1B) and the freezer showcase (1C), the internal air is cooled in the same manner as in the above-described cooling and freezing operation. After the gas refrigerant evaporated in the refrigeration heat exchanger (31) flows to the first communication gas pipe (P4), the gas refrigerant evaporated in the refrigeration heat exchanger (41) is compressed by the booster compressor (61) , Flows through the hot gas pipe (67) and the first connection gas pipe (77) to the first communication gas pipe (P4). The refrigerant in the first communication gas pipe (P4) is again drawn into the variable capacity compressor (21b) from the second low-pressure gas pipe (18).

    The refrigerant that has flowed to the supercooling heat exchanger (71) returns to the outdoor unit (1A) without being supercooled, and sequentially passes through the branch liquid pipe (17) and the receiver (24) to the auxiliary liquid pipe (16). The flow is reduced by the outdoor expansion valve (27). The decompressed refrigerant flows to the outdoor heat exchanger (23), evaporates by exchanging heat with outdoor air taken in by the outdoor fan (25), and then the first outdoor gas pipe (12) and the four-way switching valve. (22) and the first low-pressure gas pipe (15) are sequentially passed through the fixed capacity compressor (21a).

    Thus, in the second heating and refrigeration operation, the refrigerant absorbs heat in the refrigeration heat exchanger (31), the refrigeration heat exchanger (41), and the outdoor heat exchanger (23), and the refrigerant in the air conditioning heat exchanger (51). Dissipate heat. That is, the heat that the refrigerant has absorbed from the indoor air in the refrigeration heat exchanger (31) and the refrigeration heat exchanger (41) and the heat that the refrigerant has absorbed from the outdoor air in the outdoor heat exchanger (23) are used. In addition, since the inside of the store is heated, the heating capacity increases.

-Effect of the embodiment-
As described above, according to this embodiment, the liquid refrigerant in the supercooled communication liquid pipe (P1) is divided into the air conditioning unit (1D), the refrigerated showcase (1B), and the refrigerated showcase (1C), A three-way switching valve (78) is provided for switching between a state in which the branched refrigerant in the supercooling passage (74) flows to the suction side of the fixed capacity compressor (21a) and a state in which the refrigerant flows to the suction side of the variable capacity compressor (21b). As a result, the refrigerant circulation rate in the air conditioning unit (1D) and the refrigeration unit (1C) can be adjusted without breaking the balance between the discharge rate and suction rate of the fixed capacity compressor (21a) and variable capacity compressor (21b). can do. Therefore, the cooling capacity can be adjusted according to the magnitude relationship between the cooling loads in the air conditioning unit (1D) and the refrigeration unit (1C). As a result, driving efficiency can be improved.

    In the refrigeration showcase (1C), since the amount of liquid refrigerant that is the same as the circulation amount before the supercooling unit (1F) is always flowed, the refrigeration capacity can be improved reliably.

    In addition, the supercooling heat exchanger (71) and supercooling passage (74) are unitized and installed in the connecting pipe of the liquid pipe. can do.

    In addition, since the hot gas pipe (67) through which the high-temperature discharged refrigerant of the booster compressor (61) flows is passed through the supercooling unit (1F), the supercooling unit ( 1F) The air inside can be heated. That is, since the hot gas pipe (67) is used as air heating means, it is possible to suppress the temperature drop of the air in the supercooling unit (1F). Thereby, generation | occurrence | production and growth of frost in a supercooling unit (1F) can be suppressed, without providing an electric heater etc. separately.

    In particular, since the hot gas pipe (67) passes through the vicinity of the supercooling heat exchanger (71) and the upstream side passage (74a) of the supercooling passage (74), the temperature is lower than other places. Ambient air such as the supercooling heat exchanger (71) can be reliably heated. Thereby, generation | occurrence | production of the frost in a supercooling unit (1F), etc. can be suppressed reliably.

  Furthermore, since the hot gas pipe (67) passes through the upstream side passage (74a) and the supercooling heat exchanger (71) in this order, it can be heated from the upstream side passage (74a) having a low ambient temperature. Thereby, generation | occurrence | production and growth of frost in a supercooling unit (1F) can be suppressed reliably and efficiently.

    In addition to the supercooling heat exchanger (71) and the upstream passage (74a) of the supercooling passage (74), the hot gas pipe (67) passes through the vicinity of the drain outlet (DR). It is possible to prevent freezing of condensed water and the like, and to suppress the generation of frost at the drain outlet (DR) itself. As a result, it is possible to prevent the drain discharge operation from becoming difficult.

-Modification 1 of embodiment-
In the first modification, the controller (80) determines the air conditioning load or the like based on the detected pressure (intake refrigerant pressure P) of each pressure sensor (19a, 19b) instead of the air temperature T of the room temperature sensor (56) or the like. It is configured to judge the size. That is, the detected pressures of the first pressure sensor (19a) and the second pressure sensor (19b) are input to the controller (80).

    Specifically, the controller (80) is configured so that the input refrigerant pressure P of the second pressure sensor (19b) is set to a predetermined value (for example, 2 MPa) during operation of each compressor (21a, 21b). ), It is judged that the refrigeration load and the refrigeration load are small. Further, the controller (80) is configured so that the input refrigerant pressure P of the first pressure sensor (19a) is inputted from a predetermined value (for example, 4 MPa) when the compressors (21a, 21b) are operated. If it is too low, it is determined that the air conditioning load is small.

    When the controller (80) does not determine that the air conditioning load is small and determines that at least one of the refrigeration load and the refrigeration load is small, the controller (80) switches the three-way switching valve (78) to the second state. ing. The controller (80) does not determine that at least one of the refrigeration load and the refrigeration load is small, and switches the three-way switching valve (78) to the first state when determining that the air conditioning load is small. ing. On the other hand, when the controller (80) does not determine that any load is small, the controller (80) switches the three-way switching valve (78) based on the priority setting by the user as described above. Other configurations, operations, and effects are the same as those in the above embodiment.

-Modification 2 of embodiment-
In the second modification, as shown in FIG. 7, the three-way switching valve (78) is arranged not in the outdoor unit (1A) but in the supercooling unit (1F).

    Specifically, the first connection gas pipe (77) connected to the three-way switching valve (78) is extended to the outside of the supercooling unit (1F) and is in the middle of the first communication gas pipe (P4). It is connected. The second connection gas pipe (79) connected to the three-way selector valve (78) extends to the outside of the supercooling unit (1F) and is connected to the middle of the second communication gas pipe (P5). Other configurations, operations, and effects are the same as those in the above embodiment.

—Modification 3 of Embodiment—
In the third modification, as shown in FIG. 8, two two-way valves (7) are provided instead of the three-way switching valve (78). Specifically, in the outdoor unit (1A), the other end of the downstream passage (74b) extended from the supercooling unit (1F) is connected to the first connection gas pipe (77) and the second connection gas pipe (79). And branching. One two-way valve (7) is provided for each of the first connection gas pipe (77) and the second connection gas pipe (79). In the first connection gas pipe (77), the two-way valve (7) is provided upstream from the connection position of the hot gas pipe (67).

    In the case of this modification 3, the two-way valve (7) of the first connection gas pipe (77) is opened and the second connection gas pipe (79) of the second connection gas pipe (79) is open during the first cooling and refrigeration operation of the above-described embodiment. Each way valve (7) is set to the closed state. As a result, the branched refrigerant evaporated in the supercooling heat exchanger (71) returns to the variable capacity compressor (21b) of the cooling system, so that the suction pressure (low pressure) in the variable capacity compressor (21b) is extremely reduced. Can be prevented. In the second cooling / freezing operation of the above embodiment, the two-way valve (7) of the second connection gas pipe (79) is opened while the two-way valve (7) of the first connection gas pipe (77) is closed. Each state is set. As a result, the branched refrigerant evaporated in the supercooling heat exchanger (71) returns to the fixed capacity compressor (21a) of the air conditioning system, so that the suction pressure (low pressure) in the fixed capacity compressor (21a) is extremely reduced. Can be prevented. In the first or second heating / refrigeration operation of the above embodiment, at least the two-way valve (7) of the second connection gas pipe (79) is set to the closed state. Other configurations, operations, and effects are the same as those in the above embodiment.

-Modification 4 of the embodiment-
In the fourth modification, the switching control of the three-way switching valve (78) is changed in the first or second cooling / freezing operation of the above embodiment.

    Specifically, the three-way switching valve (78) of this modification not only switches to the first state and the second state described above, but also the first connection gas pipe (77) and the second connection gas pipe (79). And an intermediate state in which the refrigerant is distributed at an arbitrary ratio. Then, the controller (80) of this modified example sets the three-way switching valve (78) to the first in accordance with the change in the temperature difference between the input air temperature T and the target temperature Ta in the first or second cooling / freezing operation. It is configured to switch from the state or the second state to any intermediate state. That is, in the three-way switching valve (78), the entire branched refrigerant (100%) flows to the first connecting gas pipe (77) in the first state, and the entire branched refrigerant (100%) in the second state is the second. Flows to connecting gas pipe (79).

    In the first cooling / freezing operation, the controller (80) determines that the air conditioning load has decreased when the temperature difference between the air temperature T detected by the room temperature sensor (56) and the target temperature Ta decreases, and The switching valve (78) is switched from the first state to the intermediate state. In this intermediate state, the flow distribution ratio to the first connection gas pipe (77) and the second connection gas pipe (79) is, for example, 4: 1, and the branching refrigerant is used for the fixed capacity compressor (21a) and the variable capacity at that ratio. Flows to compressor (41). Then, the amount of refrigerant flowing from the supercooling heat exchanger (71) to the air conditioning unit (1D) is reduced by the amount of branching refrigerant flowing to the fixed capacity compressor (21a). Conversely, the amount of refrigerant flowing from the supercooling heat exchanger (71) to the refrigerated showcase (1B) increases by the reduced amount. Therefore, in the air conditioning unit (1D), the air conditioning capability is limited according to the decrease in the air conditioning load, and in the refrigerated showcase (1B), the refrigeration capability increases.

    Further, after the controller (80) switches to the intermediate state (flow rate distribution ratio is 4: 1) and the temperature difference between the air temperature T and the target temperature Ta further decreases, the controller (80) causes the three-way switching valve (78) to flow. Switching to an intermediate state where the distribution ratio is, for example, 3: 1. Thereby, since the branch refrigerant | coolant which returns to a fixed capacity compressor (21a) increases, an air conditioning capability is further restrict | limited and a refrigeration capability increases. Thus, the three-way selector valve (78) has a flow distribution ratio such that the flow rate of the branch refrigerant returning to the fixed capacity compressor (21a) increases as the temperature difference between the air temperature T and the target temperature Ta decreases. It is switched in stages. In the first cooling / freezing operation, the three-way switching valve (78) can be switched to an intermediate state with a flow rate distribution ratio of 1: 1.

    In the second cooling / freezing operation, the controller (80) determines that the refrigeration load has decreased when the temperature difference between the air temperature T detected by the refrigeration temperature sensor (36) and the target temperature Ta decreases, The path switching valve (78) is switched from the second state to the intermediate state. It is assumed that the second cooling / freezing operation is performed when it is determined that the refrigeration load is large.

    In this intermediate state, the flow rate distribution ratio to the first connection gas pipe (77) and the second connection gas pipe (79) is, for example, 1: 4. Then, the amount of refrigerant flowing from the supercooling heat exchanger (71) to the refrigerated showcase (1B) is reduced by the amount of branching refrigerant flowing to the variable capacity compressor (21b). Conversely, the amount of refrigerant flowing from the supercooling heat exchanger (71) to the air conditioning unit (1D) increases by the reduced amount. Therefore, in the air conditioning unit (1D), the air conditioning capacity increases, and in the refrigerated showcase (1B), the refrigeration capacity is limited according to the decrease in the refrigeration load. Other controls are the same as those in the first cooling / freezing operation.

    As described above, in the present modification, in the first or second cooling / freezing operation, the three-way switching valve (78) is switched to the intermediate state in accordance with the decrease in the load, and the refrigerant flow rate of the air conditioning unit (1D) or the like is changed. The limit was made in stages. Therefore, the capacity can be adjusted more finely according to the load. As a result, it is possible to operate with less waste. Other configurations, operations, and effects are the same as those in the above embodiment.

    In this modification, instead of the temperature difference between the air temperature T and the target temperature Ta, the three-way switching valve (78) may be switched to the intermediate state according to the change in the air temperature T itself. That is, when the air temperature T decreases, it is determined that the load has decreased, and the three-way switching valve (78) is switched from the first state or the second state to the intermediate state.

<< Other Embodiments >>
For example, in the above embodiment, the refrigeration showcase (1C) and the booster unit (1E) may be omitted. That is, in the present invention, it is sufficient that two or more utilization systems are provided.

    Also, three or more compressors may be used as the compression mechanism (2A) of the outdoor unit (1A). In other words, it is only necessary that the compressors used have different roles for the first usage system and for the second usage system.

    In addition, the present invention appropriately employs a hot gas pipe (67) so as to heat the vicinity of places where frost is likely to be generated other than the supercooling heat exchanger (71) and the upstream side passage (74a) of the supercooling passage (74). ) May be changed.

    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 as a refrigeration apparatus including two or more utilization systems and a compressor mainly responsible for each utilization system.

It is a refrigerant circuit figure of the refrigerating device concerning an embodiment. It is a perspective view which shows roughly the piping path | route in the supercooling unit which concerns on embodiment. It is a refrigerant circuit figure which shows operation | movement of the 1st air_conditioning | cooling freezing operation | movement of the freezing apparatus which concerns on embodiment. It is a refrigerant circuit figure which shows operation | movement of the 2nd air_conditioning | cooling freezing driving | operation of the refrigeration apparatus which concerns on embodiment. It is a refrigerant circuit figure showing operation of the 1st heating refrigerating operation of the refrigerating device concerning an embodiment. It is a refrigerant circuit figure showing operation of the 2nd heating refrigerating operation of the refrigerating device concerning an embodiment. It is a refrigerant circuit figure of the freezing apparatus which concerns on the modification 2 of embodiment. It is a refrigerant circuit figure of the freezing apparatus which concerns on the modification 3 of embodiment.

Explanation of symbols

1 Refrigeration equipment
10 Refrigerant circuit
21a Fixed capacity compressor (first compressor)
21b Variable capacity compressor (second compressor)
23 Outdoor heat exchanger (heat source side heat exchanger)
31 Refrigerated heat exchanger (use side heat exchanger)
41 Refrigeration heat exchanger (use side heat exchanger)
51 Air conditioning heat exchanger (use side heat exchanger)
61 Booster compressor (auxiliary compressor)
67 Hot gas pipe
71 Supercooling heat exchanger
74 Supercooling passage
74a Upstream passage
74b Downstream passage
75 Supercooling expansion valve (expansion mechanism)
78 Three-way switching valve (channel switching means)
80 Controller (Control means)
2A compression mechanism
1F supercooling unit
P1 Communication liquid piping (liquid pipe)

Claims (7)

The heat source system having the compression mechanism (2A) and the heat source side heat exchanger (23), and the first usage system and the second usage system having the usage side heat exchangers (31, 51) are connected, and the vapor compression refrigeration Equipped with a refrigerant circuit (10) to cycle,
The compression mechanism (2A) is a refrigeration apparatus including a first compressor (21a) mainly for a first usage system and a second compressor (21b) mainly for a second usage system,
Supercooling for supercooling the liquid refrigerant in the liquid pipe (P1) provided in the liquid pipe (P1) of the refrigerant circuit (10) and supplied by branching to the first usage system and the second usage system A heat exchanger (71),
The branch refrigerant is connected to the supercooling heat exchanger (71), and the branched refrigerant is supercooled by the branch refrigerant branched from the liquid refrigerant in the liquid pipe (P1). 71) a supercooling passage (74) for flowing through,
A first state in which the branched refrigerant after supercooling in the supercooling passage (74) flows to the suction side of the first compressor (21a), and the branched refrigerant after supercooling in the supercooling passage (74) is second compressed. A refrigeration apparatus comprising flow path switching means (78) for switching to a second state that flows to the suction side of the machine (21b). In claim 1,
The supercooling passage (74) has an expansion mechanism (75) and an upstream passage (74a) for leading the liquid phase branch refrigerant from the liquid pipe (P1) to the supercooling heat exchanger (71). A downstream passage (74b) through which the branched refrigerant after supercooling flows from the heat exchanger (71),
The flow path switching means (78) communicates the downstream passage (74b) and the suction side of the first compressor (21a) in the first state, and the downstream passage (74b) and the first passage in the second state. 2. A refrigeration apparatus configured to communicate with a suction side of a compressor (21b). In claim 2,
The second usage system has a usage side heat exchanger (41), and is connected to a third usage system in which a part of the liquid refrigerant flowing from the liquid pipe (P1) to the second usage system is branched.
The third utilization system includes a low-stage auxiliary compressor (61) for compressing the refrigerant in two stages with the second compressor (21b) of the heat source system as the high-stage side. apparatus. In claim 3,
The refrigeration apparatus, wherein the supercooling heat exchanger (71) and the supercooling passage (74) are housed in a casing to constitute a supercooling unit (1F). In claim 4,
A hot gas pipe (67) through which the refrigerant discharged from the auxiliary compressor (61) flows toward the suction side of the second compressor (21b) passes through the supercooling unit (1F). Refrigeration equipment. In claim 1 or 2,
Based on the temperature of the air that exchanges heat with the refrigerant in the use side heat exchanger (31, 51), the load state of the first use system and the second use system is determined, and according to the load state of each use system A refrigeration apparatus comprising control means (80) for switching the flow path switching means (78) between a first state and a second state. In claim 1 or 2,
Based on the suction pressures of the first compressor (21a) and the second compressor (21b), load states of the first use system and the second use system are determined, and a flow path is determined according to the load state of each use system. A refrigeration apparatus comprising control means (80) for switching the switching means (78) between a first state and a second state.

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