JP2010060181A - Refrigeration system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily configure a refrigeration system equipped with the so-called hot-and-cold corresponding showcase switching and carrying out heating and cooling of an interior. <P>SOLUTION: The refrigeration system (1) is equipped with a refrigerant circuit (10) serially connecting a compressor (11), an external heat exchanger (12), a first expansion valve (13), an HC heat exchanger (14), a second expansion valve (16), and a refrigeration heat exchanger (17). The refrigeration system (1) is equipped with a first expansion valve control part (71) controlling an opening of the first expansion valve (13) such that the refrigerant circuit (10) is switched between cooling operation of operating the external heat exchanger (12) as a radiator and operating the HC heat exchanger (14) and the refrigeration heat exchanger (17) as evaporators, and heating cooling operation of operating the external heat exchanger (12) and the HC heat exchanger (14) as a radiator and operating the refrigeration heat exchanger (17) as an evaporator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus, and particularly relates to a refrigeration apparatus including a so-called hot and cold showcase that performs switching between heating and cooling.

  Conventionally, a refrigeration apparatus including a so-called hot and cold showcase that performs switching between heating and cooling in a warehouse using a vapor compression refrigeration cycle is known (see, for example, Patent Document 1). .

  In the refrigeration apparatus, a refrigerant in which a first usage system and a second usage system having a usage-side heat exchanger that regulates the temperature in a warehouse are connected in parallel to a heat source system having a compressor and a heat source-side heat exchanger. It has a circuit. The second utilization system is provided with a low-stage auxiliary compressor for compressing the refrigerant in two stages with the compressor of the heat source system as the high-stage side. Further, the refrigeration apparatus includes a first state in which the refrigerant discharged from the auxiliary compressor flows in a gas pipe connected to the suction side of the compressor, and the refrigerant discharged between the expansion valve and the user-side heat exchanger in the first usage system. And a flow path switching means for switching to the second state.

And in the said refrigeration apparatus, by using the flow path switching means in the first state and adjusting the opening degree of the expansion valve of the first usage system, the usage side heat exchange of either the first usage system or the second usage system While the vessel performs a cooling operation for cooling the interior, the flow switching means is set to the second state and the expansion valve of the first usage system is closed, so that the usage-side heat exchanger of the first usage system is moved inside the warehouse. The heating side cooling operation which heats and the utilization side heat exchanger of the 2nd utilization system cools the inside of a warehouse was performed.
JP 2006-98044 A

  However, in the above-described refrigeration apparatus, it is possible to selectively cool and heat the inside of the first utilization system using a vapor compression refrigeration cycle. Since the operation is switched by switching the flow path, the configuration of the refrigerant circuit is complicated.

  The present invention has been made in view of the above points, and an object of the present invention is to easily configure a refrigeration apparatus including a so-called hot and cold-compatible showcase that switches between heating and cooling in a warehouse. There is to do.

  The first invention includes a heat source system (1A) having a compressor (11) and a heat source side heat exchanger (12), a first expansion valve (13), and a first use side heat exchanger (14). A refrigeration apparatus comprising a refrigerant circuit (10) connected to a first utilization system (1B) and a second utilization system (1C) having a second expansion valve (16) and a second utilization side heat exchanger (17) The compressor (11), the heat source side heat exchanger (12), the first expansion valve (13), the first usage side heat exchanger (14), the second expansion valve (16), and the second usage. Side heat exchanger (17) is connected in series, the heat source side heat exchanger (12) functions as a radiator, and the first usage side heat exchanger (14) and the second usage side heat exchanger ( The first operation in which 17) functions as an evaporator, and the heat source side heat exchanger (12) and the first usage side heat exchanger (14) function as a radiator and the second usage side heat exchanger (17 ) Function as an evaporator The second operation and to the refrigerant circuit (10) is provided with a first expansion valve control means for controlling the opening of the first expansion valve to switch (13) (71) that.

  In the first invention, the first expansion valve control means (71) controls the opening degree of the first expansion valve (13) to adjust the amount of pressure reduction of the refrigerant in the first expansion valve (13), so that the refrigerant circuit. (10) switches to the first operation and the second operation as follows.

  In the first operation, the heat source side heat exchanger (12) functions as a radiator, and the first usage side heat exchanger (14) and the second usage side heat exchanger (17) function as an evaporator. That is, in the first operation, the refrigerant sufficiently depressurized in the first expansion valve (13) flows into the first usage side heat exchanger (14), and the refrigerant is stored in the internal air of the first usage system (1B). The interior of the first usage system (1B) is cooled by evaporating with heat exchange. Further, the refrigerant that has passed through the first use side heat exchanger (14) and is further reduced in pressure in the second expansion valve (16) flows into the second use side heat exchanger (17), and the refrigerant is used in the second use valve. The interior of the second usage system (1C) is cooled by evaporating through heat exchange with the interior air of the system (1C).

  On the other hand, in the second operation, the heat source side heat exchanger (12) and the first usage side heat exchanger (14) function as a radiator and the second usage side heat exchanger (17) functions as an evaporator. That is, in the second operation, the refrigerant that has passed through the first expansion valve (13) with almost no pressure reduction flows into the first usage side heat exchanger (14), and the refrigerant is stored in the warehouse of the first usage system (1B). The interior of the first usage system (1B) is heated by exchanging heat with the internal air to dissipate heat. Moreover, the refrigerant | coolant which passed the 1st utilization side heat exchanger (14) and was pressure-reduced in the 2nd expansion valve (16) flows in into a 2nd utilization side heat exchanger (17), and this refrigerant | coolant is 2nd utilization system | strain. The interior of the second usage system (1C) is cooled by exchanging heat with the interior air of (1C) and evaporating.

  According to a second invention, in the first invention, a receiver (15) is provided between the first use side heat exchanger (14) and the second expansion valve (16) of the refrigerant circuit (10). It has been.

  By the way, at the time of a 1st driving | operation, since a 1st utilization side heat exchanger (14) functions as an evaporator, at least one part of the refrigerant | coolant which passed the 1st utilization side heat exchanger (14) is a gas refrigerant. . When such a gas refrigerant flows into the second expansion valve (16) as it is, the amount of refrigerant flowing into the second usage side heat exchanger (17) functioning as an evaporator rapidly decreases and the second usage side heat exchange is performed. The amount of heat absorbed by the refrigerant in the vessel (17) is reduced. As a result, the cooling capacity of the second usage system (1C) is reduced.

  However, in the second invention, the receiver (15) is provided between the first use side heat exchanger (14) and the second expansion valve (16). Therefore, the refrigerant that has passed through the first use side heat exchanger (14) is gas-liquid separated in the receiver (15), and only the liquid refrigerant flows into the second expansion valve (16).

  In a third aspect based on the second aspect, the refrigerant circuit (10) is provided with a bypass path (26) for bypassing the first expansion valve (13) and the first use side heat exchanger (14). In addition, the bypass passage (26) is provided with a control valve (18) having a variable opening, and the first expansion valve control means (71) is configured so that the first use side heat exchanger is in the first operation. The opening degree of the first expansion valve (13) is controlled so that the refrigerant superheat degree at the outlet of (14) becomes a predetermined value, and the first expansion valve (13) is controlled to be fully opened during the second operation. On the other hand, during the first operation, the opening degree of the control valve (18) is controlled so that the pressure difference between the refrigerant at the inlet and the outlet of the second utilization system (1C) becomes larger than a predetermined value. The valve for controlling the opening of the control valve (18) so that the internal temperature of the first usage system (1B) is in a predetermined temperature zone during the second operation. Control means (73) is provided.

  Incidentally, in the refrigeration apparatus, the compressor (11), the heat source side heat exchanger (12), the first expansion valve (13), the first use side heat exchanger (14), the second expansion valve (16), and the second The 2 use side heat exchanger (17) is connected in series. Therefore, for example, when the opening degree of the first expansion valve (13) is controlled so that the refrigerant superheat degree at the outlet of the first usage-side heat exchanger (14) becomes a predetermined value during the first operation, the first expansion valve The opening degree of (13) is adjusted according to the load fluctuation in the first usage system (1B) and the refrigerant evaporating pressure in the first usage-side heat exchanger (14) also depends on the load fluctuation in the warehouse. fluctuate. Therefore, depending on the load in the warehouse, the evaporation pressure of the first usage side heat exchanger (14) is excessively reduced, and the pressure difference between the refrigerant at the inlet and outlet of the second usage system (1C) becomes small. There is. In such a case, it becomes difficult for the refrigerant to flow into the second utilization system (1C), and the refrigeration cycle cannot be normally performed in the refrigerant circuit (10).

  However, in the third invention, a bypass passage (26) for bypassing the first expansion valve (13) and the first use side heat exchanger (14) is provided, and the first expansion valve control means is provided during the first operation. (71) controls the opening degree of the first expansion valve (13) so that the refrigerant superheat degree at the outlet of the first usage side heat exchanger (14) becomes a predetermined value, while the valve control means (73) The opening degree of the control valve (18) is controlled so that the pressure difference between the refrigerant at the inlet and the outlet of the second usage system (1C) becomes larger than a predetermined value. Thereby, the opening degree of a 1st expansion valve (13) is controlled according to the load fluctuation | variation in the store | warehouse | chamber of a 1st utilization system | strain (1B) at the time of a 1st driving | operation. Further, during the first operation, even if the opening degree of the first expansion valve (13) is controlled to be small and the evaporation pressure of the refrigerant in the first use side heat exchanger (14) is excessively reduced, the valve control means (73 ) To control the opening of the control valve (18) and adjust the amount of refrigerant flowing into the bypass (26), so that the pressure difference between the refrigerant at the inlet and outlet of the second usage system (1C) is a predetermined value. Is adjusted to be larger than Accordingly, even during the first operation, the refrigerant smoothly flows into the second usage system (1C), and the refrigeration cycle is smoothly performed in the refrigerant circuit (10).

  In the third invention, during the second operation, the first expansion valve control means (71) controls the first expansion valve (13) to the fully open state, so that the first use side heat exchanger (14) Flows out of the heat source side heat exchanger (12) and flows in a relatively high temperature refrigerant that is not decompressed. Thereby, a 1st utilization side heat exchanger (14) functions as a heat radiator. At the same time, the valve control means (73) controls the opening degree of the control valve (18) so that the internal temperature of the first usage system (1B) is in a predetermined temperature range. Thereby, the refrigerant | coolant amount which flows in into a 1st utilization side heat exchanger (14) is adjusted so that the internal temperature of a 1st utilization system | strain (1B) may become a predetermined | prescribed temperature range, and 1st utilization side heat exchange is carried out. The amount of heat exchange between the refrigerant and the internal air in the vessel (14) is adjusted.

  In a fourth aspect based on the third aspect, the first expansion valve control means (71) controls the first expansion valve (13) to a fully closed state, and the valve control means (73) controls the control. The first expansion valve control means (71) and the valve control means (73) are controlled so as to control the valve (18) to be in an open state, and the temperature control operation of the first utilization system (1B) is suspended. Thermo-off means (76) is provided.

  In the fourth invention, the first expansion valve control means (71) controls the first expansion valve (13) to the fully closed state and the valve control means (73) is controlled by the first thermo-off means (76). When the valve (18) is controlled to be in the open state, all the refrigerant discharged from the compressor (11) and radiated in the heat source side heat exchanger (12) flows into the bypass path (26), and the first usage side heat exchange is performed. Flows bypassing vessel (14). Thereby, in the 1st utilization side heat exchanger (14), heat exchange with a refrigerant and air in a warehouse is no longer performed, and the temperature control operation in the warehouse of the 1st utilization system (1B) is suspended.

  According to a fifth invention, in the third or fourth invention, the refrigerant circuit (10) includes an injection pipe that guides the gas refrigerant in the receiver (15) to an intermediate pressure compression chamber of the compressor (11). (27) is connected.

  In 5th invention, the gas refrigerant which flowed in in the receiver (15) via the 1st utilization side heat exchanger (14) or bypass channel (26) is a compressor (11) via an injection pipe (27). Is sucked into a compression chamber of intermediate pressure. As a result, the superheated steam in the middle of compression in the intermediate pressure compression chamber of the compressor (11) is cooled by the refrigerant from the injection pipe (27).

  In a sixth aspect based on the fifth aspect, the valve control means (73) is controlled so that the valve control means (73) controls the control valve (18) to a fully closed state during the first operation. In addition, second thermo-off means (77) for controlling the second expansion valve (16) to a fully closed state and stopping the temperature control operation of the second utilization system (1C) is provided.

  In the sixth aspect of the invention, the second thermo-off means (77) controls the valve control means (73) so as to control the control valve (18) to the fully closed state, and the second expansion valve (16) is fully When controlled to the closed state, the refrigerant discharged from the compressor (11) and dissipating heat in the heat source side heat exchanger (12) passes through the first expansion valve (13) and the first usage side heat exchanger (14). After passing through and flowing into the receiver (15), it does not flow into the second user-side heat exchanger (17), but is sucked into the compression chamber of the intermediate pressure of the compressor (11) via the injection pipe (27) Is done. Thereby, in the 2nd utilization side heat exchanger (17), heat exchange with a refrigerant | coolant and air in a warehouse is no longer performed, and the temperature control operation in the warehouse of a 2nd utilization system (1C) is suspended.

  In a seventh aspect based on the first or second aspect, the first expansion valve control means (71) is configured so that the evaporation pressure of the refrigerant in the first use side heat exchanger (14) is a predetermined value during the first operation. While the opening degree of the first expansion valve (13) is controlled so as to become, the first expansion valve (13) is controlled to be fully opened during the second operation.

  Incidentally, in the refrigeration apparatus, the first expansion valve (13), the first usage side heat exchanger (14), the second expansion valve (16), and the second usage side heat exchanger (17) are connected in series. ing. Therefore, for example, when the opening degree of the first expansion valve (13) is controlled according to the load fluctuation in the first usage system (1B) during the first operation, the first usage side heat exchanger ( The refrigerant evaporating pressure in 14) fluctuates according to the load fluctuation in the cabinet. Therefore, depending on the load in the warehouse, the evaporation pressure of the first usage side heat exchanger (14) is excessively reduced, and the pressure difference between the refrigerant at the inlet and outlet of the second usage system (1C) becomes small. There is. In such a case, it becomes difficult for the refrigerant to flow into the second utilization system (1C), and the refrigeration cycle cannot be normally performed in the refrigerant circuit (10).

  However, in the seventh invention, during the first operation, the opening of the first expansion valve (13) is controlled so that the evaporation pressure of the refrigerant in the first use side heat exchanger (14) becomes a predetermined value. Therefore, since the refrigerant pressure at the inlet of the second usage system (1C) is controlled to be constant, the pressure difference between the refrigerant at the inlet and outlet of the second usage system (1C) is adjusted to be increased to some extent. Thereby, also at the time of a 1st driving | operation, a refrigerant | coolant flows into a 2nd utilization system | strain (1C) smoothly, and a refrigeration cycle will be performed smoothly in a refrigerant circuit (10).

  In the seventh aspect of the invention, during the second operation, the first expansion valve control means (71) controls the first expansion valve (13) to the fully open state, so that the first use side heat exchanger (14) Flows out of the heat source side heat exchanger (12) and flows in a relatively high temperature refrigerant that is not decompressed. Thereby, a 1st utilization side heat exchanger (14) functions as a heat radiator, and the interior of a 1st utilization system (1B) is heated.

  According to the present invention, the compressor (11), the heat source side heat exchanger (12), the first expansion valve (13), the first use side heat exchanger (14), the second expansion valve (16), and the second By connecting the use side heat exchanger (17) in series, the first operation in which the interiors of the first use system (1B) and the second use system (1C) are cooled together, and the first use system ( In the second operation in which the interior of the cabinet of 1B) is heated and the interior of the compartment of the second utilization system (1C) is cooled, the first expansion valve (13) is simply controlled by opening the first expansion valve (13). It can be switched by adjusting the amount of pressure reduction in (). Therefore, it is not necessary to use different flow paths and flow path switching means to switch between the first operation and the second operation, and the configuration of the refrigerant circuit (10) can be facilitated. Therefore, according to the present invention, it is possible to easily configure the refrigeration apparatus (1) including a hot and cold showcase that heats or cools the inside of the warehouse.

  According to the second invention, since the receiver (15) is provided between the first use side heat exchanger (14) and the second expansion valve (16), the first use side heat exchanger is provided. The refrigerant that has passed (14) can be gas-liquid separated in the receiver (15). As a result, only the liquid refrigerant can flow into the second expansion valve (16). Accordingly, it is possible to prevent the cooling capacity of the second usage system (1C) from being lowered even during the first operation in which the first usage-side heat exchanger (14) functions as an evaporator.

  Further, according to the third invention, during the first operation, the opening degree of the first expansion valve (13) can be controlled according to the load fluctuation in the warehouse of the first usage system (1B). Further, during the first operation, even if the opening degree of the first expansion valve (13) is controlled to be small and the evaporation pressure of the refrigerant in the first use side heat exchanger (14) is excessively reduced, the valve control means (73 ) Controls the opening of the control valve (18) to adjust the amount of refrigerant flowing into the bypass (26), so that the pressure difference between the refrigerant at the inlet and outlet of the second usage system (1C) is a predetermined value. Can be adjusted to be larger. Accordingly, even during the first operation, the refrigerant can smoothly flow into the second utilization system (1C), and the refrigeration cycle can be smoothly performed in the refrigerant circuit (10).

  Further, according to the third invention, during the second operation, the first expansion valve control means (71) controls the first expansion valve (13) to the fully open state and flows out of the heat source side heat exchanger (12). Thus, the first use-side heat exchanger (14) can easily function as a radiator by allowing the relatively high-temperature refrigerant that has not been decompressed to flow into the first use-side heat exchanger (14). . At the same time, the valve control means (73) controls the opening of the control valve (18) and adjusts the amount of refrigerant flowing into the bypass passage (26), so that the first use side heat exchanger ( 14) The amount of refrigerant passing through can be adjusted. Thereby, the temperature in the store | warehouse | chamber of a 1st utilization system | strain (1B) can be adjusted to a predetermined temperature range.

  Further, according to the fourth invention, by providing the bypass passage (26), the refrigerant circuit (10) can perform the refrigeration cycle even when the first expansion valve (13) is fully closed. Therefore, controlled by the first thermo-off means (76), the first expansion valve control means (71) controls the first expansion valve (13) to the fully closed state, and the valve control means (73) is controlled by the control valve (18). By controlling to the open state, the temperature control operation in the warehouse of the first usage system (1B) can be suspended.

  Further, according to the fifth aspect of the present invention, the injection pipe (27) that guides the gas refrigerant in the receiver (15) to the compression chamber of the intermediate pressure of the compressor (11) is provided. The inflowing gas refrigerant can be sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). As a result, the superheated steam in the middle of compression in the compression chamber of the intermediate pressure of the compressor (11) can be cooled by the refrigerant from the injection pipe (27). Therefore, the compressor efficiency can be improved.

  Further, according to the sixth invention, by providing the injection pipe (27), the refrigeration cycle can be performed in the refrigerant circuit (10) even when the second expansion valve (16) is fully closed. . Therefore, the second thermo-off means (77) controls the valve control means (73) to control the control valve (18) to be fully closed, and the second expansion valve (16) is controlled to be fully closed. By doing so, the temperature control operation in the store | warehouse | chamber of a 2nd utilization system | strain (1C) can be stopped.

  Further, according to the seventh invention, during the first operation, the first expansion valve control means (71) determines the degree of opening of the first expansion valve (13) by evaporating the refrigerant in the first use side heat exchanger (14). By controlling the pressure to be a predetermined value, the refrigerant pressure at the inlet of the second usage system (1C) remains constant and does not decrease. Therefore, the refrigerant pressure at the inlet and outlet of the second usage system (1C) It is possible to keep the difference from being smaller than a certain size. Accordingly, even during the first operation, the refrigerant can smoothly flow into the second utilization system (1C), and the refrigeration cycle can be smoothly performed in the refrigerant circuit (10).

  Further, according to the seventh invention, during the second operation, the first expansion valve control means (71) controls the first expansion valve (13) to the fully open state and flows out of the heat source side heat exchanger (12). Thus, the first use-side heat exchanger (14) can easily function as a radiator by allowing the relatively high-temperature refrigerant that has not been decompressed to flow into the first use-side heat exchanger (14). .

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

-Overall configuration-
The refrigeration apparatus of this embodiment performs heating and cooling in the showcase. As shown in FIG. 1, the refrigeration apparatus (1) includes an external unit (1A), a hot and cold unit for cooling or heating the inside of the showcase (hereinafter referred to as HC unit (1B)), and a showcase. And a controller (100), which is a cooling-only unit (hereinafter simply referred to as a cooling unit (1C)) that only cools the inside. The refrigeration apparatus (1) includes a refrigerant circuit (10) in which an external unit (1A), an HC unit (1B), and a cooling unit (1C) are connected in series to perform a refrigeration cycle.

<Outside unit>
The external unit (1A) includes a compressor (11) and an external heat exchanger (12) that is a heat source side heat exchanger according to the present invention, and constitutes a heat source system.

  The compressor (11) is configured by a hermetically sealed high-pressure dome type scroll compressor, and a compression mechanism in which a plurality of compression chambers are formed and an electric motor for driving the compression mechanism are housed in a casing. ing. The compressor (11) has a variable operating capacity. Specifically, the compressor (11) is constituted by an inverter compressor, and is configured to be variable in capacity by changing the output frequency of the inverter and changing the rotational speed of the electric motor. The operating capacity (rotational speed of the electric motor) of the compressor (11) is controlled by a compressor control unit (74) of the controller (100) described later.

  The compressor (11) is formed with a suction port for sucking the refrigerant and a discharge port for discharging the compressed refrigerant. One end of the gas pipe (25) is connected to the suction port, and one end of the discharge pipe (21) is connected to the discharge port. The compressor (11) compresses the refrigerant sucked from the gas pipe (25) through the suction port in the compression chamber and discharges the refrigerant to the discharge pipe (21) through the discharge port. A shutoff valve (34) is provided at the end of the gas pipe (25) on the HC unit (1B) side in the external unit (1A).

  The compressor (11) is formed with an intermediate port that opens to a compression chamber of intermediate pressure among the plurality of compression chambers. One end of an injection pipe (27) is connected to the intermediate port. The injection pipe (27) is provided with a check valve (31) that allows only the refrigerant to flow from the intermediate port into the compression chamber of the intermediate pressure of the compressor (11). In addition, a closing valve (33) is provided at the end of the injection pipe (27) on the HC unit (1B) side in the external unit (1A).

  The external heat exchanger (12) is configured by, for example, a cross fin type fin-and-tube heat exchanger. An external fan (12a) is disposed close to the external heat exchanger (12). The outside fan (12a) is configured such that the rotation speed is variable, and the rotation speed is controlled by the outside fan control section (75) of the controller (100) described later. The other end of the discharge pipe (21) is connected to the gas side end of the external heat exchanger (12), and one end of the liquid pipe (22) is connected to the liquid side end. A closing valve (32) is provided at the end of the liquid pipe (22) on the cooling unit (1C) side in the external unit (1A).

<HC unit>
The HC unit (1B) constitutes a first utilization system that cools and heats food and the like (for example, canned coffee). The HC unit (1B) includes a first expansion valve (13), an HC heat exchanger (14) which is a first use side heat exchanger according to the present invention, and a receiver (15).

  The HC heat exchanger (14) is constituted by, for example, a cross fin type fin-and-tube heat exchanger, and is configured such that heat is exchanged between the refrigerant and the air in the showcase. One end of the HC heat exchanger (14) is connected to the other end of the liquid pipe (22), and the other end of the HC heat exchanger (14) is connected to one end of the inflow pipe (23). . Further, the HC internal fan (14a) is disposed close to the HC heat exchanger (14).

  The first expansion valve (13) is provided near the HC heat exchanger (14) of the liquid pipe (22). The first expansion valve (13) has a variable opening. The opening degree of the first expansion valve (13) is controlled by a first expansion valve control unit (71) included in the control means (70) of the controller (100) described later.

  The receiver (15) is connected to the other end of the inflow pipe (23) and one end of the outflow pipe (24). The receiver (15) is configured to temporarily store the refrigerant flowing in from the inflow pipe (23), separate the liquid refrigerant from the gas refrigerant, and allow only the liquid refrigerant to flow out from the outflow pipe (24). Yes. The outflow pipe (24) extends toward the cooling unit (1C).

  A bypass pipe (26) is connected to the receiver (15). One end of the bypass pipe (26) is connected to the external unit (1A) side of the liquid pipe (22) from the first expansion valve (13), and the other end is connected to the receiver (15). That is, the bypass pipe (26) is disposed so as to bypass the first expansion valve (13) and the HC heat exchanger (14) in the refrigerant circuit (10). The bypass pipe (26) is provided with a third expansion valve (18) having a variable opening degree. The opening degree of the third expansion valve (18) is controlled by a third expansion valve control unit (73) included in the control means (70) of the controller (100) described later.

  Furthermore, the other end of the injection pipe (27) is connected to the receiver (15). The injection pipe (27) extends toward the external unit (1A). The injection pipe (27) is configured to guide only the gas refrigerant separated from the liquid refrigerant in the receiver (15) to the intermediate pressure compression chamber of the compressor (11).

<Cooling unit>
The cooling unit (1C) constitutes a second utilization system that cools food and the like. The cooling unit (1C) includes a second expansion valve (16) and a refrigeration heat exchanger (17) that is a second use side heat exchanger according to the present invention.

  The refrigeration heat exchanger (17) is constituted by, for example, a cross fin type fin-and-tube heat exchanger, and is configured such that heat is exchanged between the refrigerant and the air in the showcase. The other end of the outflow pipe (24) is connected to one end of the refrigeration heat exchanger (17), and the other end of the gas pipe (25) is connected to the other end of the refrigeration heat exchanger (17). It is connected. In addition, a refrigeration internal fan (17a) is disposed close to the refrigeration heat exchanger (17).

  The second expansion valve (16) is provided near the refrigeration heat exchanger (17) of the outflow pipe (24). The second expansion valve (16) has a variable opening. The opening degree of the second expansion valve (16) is controlled by the second expansion valve control unit (72) included in the control means (70) of the controller (100) described later.

  With the above configuration, in the refrigerant circuit (10), the compressor (11), the external heat exchanger (12), the first expansion valve (13), the HC heat exchanger (14), and the second expansion valve ( 16) and the refrigeration heat exchanger (17) are connected in series.

<Control system>
The refrigerant circuit (10) is provided with various sensors and various switches.

  The discharge pipe (21) of the external unit (1A) is provided with a high pressure sensor (81) for detecting the pressure of refrigerant discharged from the compressor (11). The gas pipe (25) of the external unit (1A) is provided with a low pressure sensor (82) that detects the pressure of the refrigerant sucked in the compressor (11). Further, an outside air temperature sensor (83) for detecting the outside air temperature is provided in the vicinity of the outside fan (12a) of the outside unit (1A).

  The heat transfer tube of the HC heat exchanger (14) of the HC unit (1B) is provided with a first temperature sensor (84) for detecting the condensation temperature or evaporation temperature of the refrigerant. The inlet pipe (23) of the HC unit (1B) is provided with a first outlet temperature sensor (85) for detecting the temperature of the refrigerant flowing out of the HC heat exchanger (14). Furthermore, a first internal temperature sensor (86) for detecting the internal temperature is provided in the vicinity of the HC internal fan (14a) of the HC unit (1B). In addition, the injection pipe (27) of the HC unit (1B) detects the pressure of the refrigerant in the injection pipe (27) and sucked into the compression chamber of the intermediate pressure of the compressor (11). An intermediate pressure sensor (87) is provided.

  The heat transfer tube of the refrigeration heat exchanger (17) of the cooling unit (1C) is provided with a second temperature sensor (88) for detecting the evaporation temperature of the refrigerant. The gas pipe (25) of the cooling unit (1C) is provided with a second outlet temperature sensor (89) for detecting the temperature of the refrigerant flowing out of the refrigeration heat exchanger (17). Further, a second internal temperature sensor (90) for detecting the internal temperature is provided in the vicinity of the internal refrigerator fan (17a) of the cooling unit (1C).

  The various sensors are connected to the controller (100), and output signals of the various sensors are input to the controller (100).

  The controller (100) includes a control means (70), a compressor control unit (74), and an external fan control unit (75).

  The control means (70) includes the first expansion valve control unit (71), the second expansion valve control unit (72), and the third expansion valve control unit (73). As described above, the first expansion valve control unit (71) controls the opening degree of the first expansion valve (13), and the second expansion valve control unit (72) sets the opening degree of the second expansion valve (16). And the third expansion valve control unit (73) is configured to control the opening degree of the third expansion valve (18). The control means (70) controls the opening degree of each expansion valve (13, 16, 18) by means of the first to third expansion valve control sections (71, 72, 73), so that the refrigerant circuit ( Switch the refrigeration cycle performed in 10).

  The compressor control unit (74) mainly operates the operating capacity of the compressor (11) (rotational speed of the electric motor) in order to suitably perform the refrigeration cycle switched by the control means (70) mainly in the refrigerant circuit (10). To control.

  The outside fan control unit (75), similar to the compressor control unit (74), mainly stores the refrigerant circuit (10) in order to suitably perform the refrigeration cycle switched by the control means (70) in the refrigerant circuit (10). Controls the rotation speed of the outer fan (12a).

  The controller (100) also pauses the first thermo-off means (76) for stopping the temperature control operation in the showcase of the HC unit (1B) and the temperature control operation in the showcase of the cooling unit (1C). Second thermo-off means (77).

-Driving action-
In the refrigeration system (1), the cooling operation for cooling the inside of the showcase of the HC unit (1B) and the cooling unit (1C), and the showcase of the cooling unit (1C) for heating the inside of the showcase of the HC unit (1B) A heating / cooling operation for cooling the inside is performed.

  In the refrigeration system (1), the temperature control operation (heating or cooling) in the showcase of the HC unit (1B) is stopped by the first thermo-off means (76), and the showcase of the cooling unit (1C) is displayed. A first thermo-off operation is performed in which only temperature control (cooling) is performed. Further, in the refrigeration apparatus (1), the temperature control operation (cooling) in the showcase of the cooling unit (1C) is stopped by the second thermo-off means (77), and the temperature in the showcase of the HC unit (1B) is stopped. A second thermo-off operation is performed in which only the adjustment (cooling) is performed. Hereinafter, each driving | operation operation | movement is explained in full detail.

<Cooling operation>
In the cooling operation, the first expansion valve controller (71) of the control means (70) is configured such that the external heat exchanger (12) functions as a radiator in the refrigerant circuit (10) and the HC heat exchanger (14) and The refrigeration heat exchanger (17) is switched by controlling the opening of the first expansion valve (13) so that a refrigeration cycle is performed in which the evaporator functions as an evaporator.

  Specifically, the first expansion valve control unit (71) controls the first expansion valve (13) so that the degree of superheat of the refrigerant flowing out of the HC heat exchanger (14) becomes a predetermined value (for example, 5 ° C.). To control the opening degree. For example, the first expansion valve control unit (71) causes the detection value of the first outlet temperature sensor (85) to be higher by a predetermined value (for example, 5 ° C.) than the detection value of the first temperature sensor (84). The opening degree of the first expansion valve (13) is controlled.

  Further, at this time, the second expansion valve control unit (72) controls the second expansion valve (16) so that the degree of superheat of the refrigerant flowing out of the refrigeration heat exchanger (17) becomes a predetermined value (for example, 5 ° C.). ) Is controlled. For example, the second expansion valve control unit (72) causes the detection value of the second outlet temperature sensor (89) to be higher by a predetermined value (for example, 5 ° C.) than the detection value of the second temperature sensor (88). The opening degree of the second expansion valve (16) is controlled.

  The third expansion valve controller (73) controls the opening of the third expansion valve (18) so that the pressure difference between the refrigerant at the inlet and the outlet of the cooling unit (1C) is equal to or greater than a predetermined value. For example, the third expansion valve control unit (73) refers to the detection value (intermediate pressure) of the intermediate pressure sensor (87) and the detection value (low pressure) of the low pressure sensor (82), and determines the intermediate pressure and the low pressure. The degree of opening of the third expansion valve (18) is controlled so that the differential pressure between the first and second expansion valves is greater than a predetermined value (7 kPa).

  The compressor control unit (74) refers to the detection value of the low pressure sensor (82) and controls the operating capacity (rotational speed of the motor) of the compressor (11) so that the detection value becomes a predetermined value. To do. The predetermined value is, for example, a saturation pressure (temperature-equivalent saturation pressure) corresponding to a temperature that is 10 ° C. lower than the set temperature inside the cooling unit (1C).

  The outside fan control unit (75) refers to the detected value of the outside air temperature sensor (83), the detected value of the high pressure sensor (81), and the detected value of the low pressure sensor (82). The outside fan control unit (75) has a predetermined value (for example, a value obtained by subtracting the outside air temperature from the saturation temperature (high pressure equivalent saturation temperature) corresponding to the detection value (high pressure) of the high pressure sensor (81). 15 ° C.) or less, and the differential pressure between the detected value (high pressure) of the high pressure sensor (81) and the detected value (low pressure) of the low pressure sensor (82) is larger than a predetermined value (for example, 10 kPa). In addition, the rotational speed of the external fan (12a) is controlled.

  Through the control as described above, the high-temperature and high-pressure gas refrigerant compressed in the compressor (11) flows into the external heat exchanger (12) through the discharge pipe (21). In the external heat exchanger (12), the refrigerant radiates heat to the external air. Then, the refrigerant flows into the HC unit (1B) through the liquid pipe (22).

  In the HC unit (1B), the refrigerant flows into the first expansion valve (13) and is decompressed by the first expansion valve (13) to become a low-temperature and low-pressure refrigerant. Then, it flows into the HC heat exchanger (14) and absorbs heat from the air in the showcase to evaporate in the HC heat exchanger (14). Thereby, the air in the showcase of the HC unit (1B) is cooled.

  In the present embodiment, as described above, the degree of superheat of the refrigerant flowing out of the HC heat exchanger (14) is set to a predetermined value (for example, 5 ° C.) by the first expansion valve control unit (71). The opening degree of the first expansion valve (13) is controlled. Therefore, all the refrigerant evaporates into the gas refrigerant in the HC heat exchanger (14) and flows into the receiver (15) through the inflow pipe (23).

  In the present embodiment, as described above, the third expansion valve (73) controls the third expansion valve (73) so that the refrigerant pressure difference between the inlet and outlet of the cooling unit (1C) is equal to or greater than a predetermined value. The opening degree of 18) is controlled. Therefore, the refrigerant that has flowed into the HC unit (1B) also flows into the bypass pipe (26), is decompressed in the third expansion valve (18), and then flows into the receiver (15).

  The refrigerant that has flowed into the receiver (15) through the inflow pipe (23) and the bypass pipe (26) is separated into gas and liquid in the receiver (15). Then, the gas refrigerant separated from the liquid refrigerant is sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). On the other hand, the liquid refrigerant flows into the outflow pipe (24).

  The refrigerant that has flowed into the outflow pipe (24) flows into the cooling unit (1C) and is depressurized by the second expansion valve (16) to become a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant flows into the refrigeration heat exchanger (17), and absorbs heat from the air in the showcase and evaporates in the refrigeration heat exchanger (17). Thereby, the air in the showcase of the cooling unit (1C) is cooled.

  As described above, the second expansion valve controller (72) causes the second expansion valve so that the degree of superheat of the refrigerant flowing out of the refrigeration heat exchanger (17) becomes a predetermined value (for example, 5 ° C.). The opening degree of (16) is controlled. Therefore, all the refrigerant evaporates in the refrigeration heat exchanger (17) to become a gas refrigerant, and is sucked into the compressor (11) from the suction port via the gas pipe (25). Then, the refrigerant is compressed again in the compressor (11) and discharged to the discharge pipe (21).

  The intermediate pressure gas refrigerant is sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). Thereby, the superheated steam in the middle of compression in the compression chamber of the intermediate pressure of the compressor (11) is cooled by the refrigerant from the injection pipe (27). As a result, the compressor efficiency is improved.

  By repeating the above operation, the inside of the showcase of the HC unit (1B) and the inside of the showcase of the cooling unit (1C) are cooled.

<Heating / cooling operation>
In the heating / cooling operation, the first expansion valve control unit (71) of the control means (70) is configured such that the external heat exchanger (12) and the HC heat exchanger (14) function as a radiator in the refrigerant circuit (10). The refrigeration heat exchanger (17) is switched by controlling the opening degree of the first expansion valve (13) so that a refrigeration cycle in which the evaporator (17) functions as an evaporator is performed.

  Specifically, the first expansion valve control unit (71) controls the opening of the first expansion valve (13) to a fully open state.

  At this time, the second expansion valve control unit (72) controls the opening degree of the second expansion valve (16) in the same manner as in the cooling operation.

  In addition, the third expansion valve control unit (73) controls the third expansion valve (18) so that the temperature in the showcase of the HC unit (1B) becomes a predetermined target temperature range (for example, 40 ° C. to 45 ° C.). To control the opening degree. For example, the third expansion valve control unit (73) refers to the detection value of the first internal temperature sensor (86), and when the air temperature in the showcase of the HC unit (1B) is within the target temperature range, While the 3 expansion valve (18) is controlled to be fully closed, when the air temperature in the showcase exceeds the upper limit value (for example, 45 ° C.) of the target temperature range, the third expansion valve (18) is opened to a predetermined degree. Just open.

  The compressor control unit (74) controls the operating capacity (rotational speed of the electric motor) of the compressor (11) in the same manner as in the cooling operation.

  Further, the external fan control unit (75) refers to the detection value of the first internal temperature sensor (86), and the air temperature in the showcase of the HC unit (1B) is set to a target temperature range (for example, 40 ° C to 40 ° C). The rotational speed of the external fan (12a) is controlled so that the temperature is within 45 ° C.

  Through the control as described above, the high-temperature and high-pressure gas refrigerant compressed in the compressor (11) flows into the external heat exchanger (12) through the discharge pipe (21). In the external heat exchanger (12), the refrigerant radiates heat to the external air. Then, the refrigerant flows into the HC unit (1B) through the liquid pipe (22).

  In the HC unit (1B), the refrigerant flows into the HC heat exchanger (14) at a relatively high temperature without being reduced in pressure in the fully opened first expansion valve (13). The refrigerant radiates heat to the air in the showcase in the HC heat exchanger (14). Thereby, the air in the showcase of the HC unit (1B) is heated. Then, the refrigerant that has flowed out of the HC heat exchanger (14) flows into the receiver (15) through the inflow pipe (23).

  Note that when the air temperature in the showcase of the HC unit (1B) is within a target temperature range (for example, 40 ° C. to 45 ° C.), the third expansion valve (18) is in a fully closed state, so that the refrigerant is bypassed. Does not flow into (26). On the other hand, when the air temperature in the showcase of the HC unit (1B) exceeds the upper limit value (for example, 45 ° C.) of the target temperature range (for example, 40 ° C. to 45 ° C.), the third expansion valve (18) is opened. Therefore, a part of the refrigerant that has flowed into the HC unit (1B) flows into the bypass pipe (26), is decompressed by the third expansion valve (18), and then flows into the receiver (15). Thereby, the refrigerant | coolant amount which flows in into HC heat exchanger (14) reduces, and the thermal radiation amount of the refrigerant | coolant in HC heat exchanger (14) reduces. As a result, the air temperature in the showcase of the HC unit (1B) gradually decreases and approaches the target temperature range.

  The refrigerant flowing into the receiver (15) is separated into gas and liquid at the receiver (15). Then, the gas refrigerant separated from the liquid refrigerant is sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). On the other hand, the liquid refrigerant flows into the outflow pipe (24).

  The refrigerant that has flowed into the outflow pipe (24) flows into the cooling unit (1C) and is depressurized by the second expansion valve (16) to become a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant flows into the refrigeration heat exchanger (17), and absorbs heat from the air in the showcase and evaporates in the refrigeration heat exchanger (17). Thereby, the air in the showcase of the cooling unit (1C) is cooled.

  As described above, the second expansion valve controller (72) causes the second expansion valve so that the degree of superheat of the refrigerant flowing out of the refrigeration heat exchanger (17) becomes a predetermined value (for example, 5 ° C.). The opening degree of (16) is controlled. Therefore, all the refrigerant evaporates in the refrigeration heat exchanger (17) to become a gas refrigerant, and is sucked into the compressor (11) from the suction port via the gas pipe (25). Then, the refrigerant is compressed again in the compressor (11) and discharged to the discharge pipe (21).

  The intermediate pressure gas refrigerant is sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). Thereby, the superheated steam in the middle of compression in the compression chamber of the intermediate pressure of the compressor (11) is cooled by the refrigerant from the injection pipe (27). As a result, the compressor efficiency is improved.

  By repeating the above operation, the inside of the showcase of the HC unit (1B) is heated, while the inside of the showcase of the cooling unit (1C) is cooled.

<First thermo-off operation>
In the first thermo-off operation, during the cooling operation and heating / cooling operation, the first thermo-off means (76) controls the first expansion valve control unit (71) so that the first expansion valve (13) is fully closed. The first expansion valve control unit (73) controls the first expansion valve control unit (71) and the third expansion valve control unit (73) so that the third expansion valve (18) is controlled to be fully opened. It is switched by.

  At this time, the control by the second expansion valve control unit (72) and the compressor control unit (74) is the same as in the cooling operation and the heating / cooling operation, and the control by the external fan control unit (75) is the cooling. It is the same as when driving.

  Through the control as described above, the refrigerant circulates in the refrigerant circuit (10) as shown in FIG.

  Specifically, as in the cooling operation and the heating / cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor (11) passes through the external heat exchanger (12) and passes through the HC unit ( 1B).

  In the HC unit (1B), the refrigerant flows only into the bypass pipe (26) without flowing into the HC heat exchanger (14) because the first expansion valve (13) is fully closed. The refrigerant flowing into the bypass pipe (26) flows into the receiver (15) without being depressurized by the third expansion valve (18) because the third expansion valve (18) is controlled to be fully opened. In this way, in the HC unit (1B), the refrigerant bypasses the HC heat exchanger (14) and flows into the receiver (15).

  Since the subsequent operation of the refrigerant is the same as that during the cooling operation and the heating / cooling operation, description thereof is omitted.

  With the above operation, heating or cooling in the showcase of the HC unit (1B) is suspended, while the showcase of the cooling unit (1C) is cooled.

<Second thermo-off operation>
In the second thermo-off operation, during the cooling operation, the second thermo-off means (77) controls the second expansion valve (16) to the fully closed state by the second expansion valve control unit (72), and the third expansion valve The control unit (73) is switched by controlling the second expansion valve control unit (72) and the third expansion valve control unit (73) so as to control the third expansion valve (18) to the fully closed state.

  At this time, the control by the first expansion valve control unit (71) is the same as in the cooling operation.

  The outside fan control unit (75) refers to the detected value of the outside air temperature sensor (83), the detected value of the high pressure sensor (81), and the detected value of the intermediate pressure sensor (87). The outside fan control unit (75) has a predetermined value (for example, a value obtained by subtracting the outside air temperature from the saturation temperature (high pressure equivalent saturation temperature) corresponding to the detection value (high pressure) of the high pressure sensor (81). 15 ° C.) or less, and the difference between the detected value (high pressure) of the high pressure sensor (81) and the detected value of the intermediate pressure sensor (87) is larger than a predetermined value (for example, 10 kPa). The rotational speed of (12a) is controlled.

  Through the control as described above, the refrigerant circulates in the refrigerant circuit (10) as shown in FIG.

  Specifically, in the same manner as in the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor (11) passes through the external heat exchanger (12) and flows into the HC unit (1B). The HC heat exchanger (14) absorbs heat from the air in the showcase to cool the inside of the showcase. And the gas refrigerant which flowed out from HC heat exchanger (14) flows into a receiver (15).

  Since the third expansion valve (18) is controlled to be fully closed, the refrigerant flowing into the HC unit (1B) does not flow into the bypass pipe (26).

  The gas refrigerant flowing into the receiver (15) is sucked from the receiver (15) through the injection pipe (27) into an intermediate pressure compression chamber of the compressor (11). The refrigerant is compressed in the compression chamber and discharged to the discharge pipe (21).

  Since the second expansion valve (16) is fully closed, the refrigerant in the receiver (15) does not flow into the refrigeration heat exchanger (17).

  With the above operation, the inside of the showcase of the HC unit (1B) is cooled, and the temperature control (cooling) in the showcase of the cooling unit (1C) is stopped.

-Effect of Embodiment 1-
According to this refrigeration apparatus (1), the compressor (11), the external heat exchanger (12), the first expansion valve (13), the HC heat exchanger (14), the second expansion valve (16), and the refrigerator By connecting the heat exchanger for heat (17) in series, the cooling operation in which the inside of the showcase of the HC unit (1B) and the cooling unit (1C) is cooled together, and the inside of the showcase of the HC unit (1B) The heating and cooling operation in which the inside of the showcase of the cooling unit (1C) is heated is simply controlled by controlling the opening of the first expansion valve (13) to adjust the amount of pressure reduction in the first expansion valve (13). Can be switched. Therefore, it is not necessary to use different flow paths and flow path switching means for switching between the cooling operation and the heating / cooling operation, and the configuration of the refrigerant circuit (10) can be facilitated. Therefore, according to the refrigeration apparatus (1), the refrigeration apparatus (1) including a hot and cold showcase can be easily configured.

  By the way, since the HC heat exchanger (14) functions as an evaporator during the cooling operation, at least a part of the refrigerant that has passed through the HC heat exchanger (14) is a gas refrigerant. When such a gas refrigerant flows into the second expansion valve (16) as it is, the amount of refrigerant flowing into the refrigeration heat exchanger (17) functioning as an evaporator rapidly decreases and the refrigeration heat exchanger (17). The amount of heat absorbed by the refrigerant becomes smaller. As a result, the cooling capacity of the cooling unit (1C) is reduced.

  However, according to the refrigeration apparatus (1), the receiver (15) is provided between the HC heat exchanger (14) and the second expansion valve (16). As a result, the refrigerant that has passed through the HC heat exchanger (14) can be gas-liquid separated in the receiver (15), and only the liquid refrigerant can flow into the second expansion valve (16). Accordingly, it is possible to prevent the refrigeration capacity of the refrigerant circuit (10) from being lowered even during the cooling operation in which the HC heat exchanger (14) functions as an evaporator.

  In the refrigeration apparatus (1), the compressor (11), the external heat exchanger (12), the first expansion valve (13), the HC heat exchanger (14), the second expansion valve (16), and the refrigerator The heat exchanger (17) for use is connected in series. Therefore, for example, when the opening degree of the first expansion valve (13) is controlled so that the refrigerant superheat degree at the outlet of the HC heat exchanger (14) becomes a predetermined value during the cooling operation, the first expansion valve ( The opening degree of 13) is adjusted according to the load fluctuation in the showcase of the HC unit (1B), and the evaporation pressure of the refrigerant in the HC heat exchanger (14) also fluctuates according to the load fluctuation in the showcase. Therefore, depending on the load in the showcase, the evaporation pressure of the HC heat exchanger (14) may be excessively reduced, and the pressure difference between the refrigerant at the inlet and outlet of the cooling unit (1C) may be reduced. In such a case, it becomes difficult for the refrigerant to flow into the cooling unit (1C), and the refrigeration cycle cannot be normally performed in the refrigerant circuit (10).

  However, in the present refrigeration apparatus (1), a bypass pipe (26) that bypasses the first expansion valve (13) and the HC heat exchanger (14) is provided, and during the cooling operation, the first expansion valve control unit (71 ) To control the opening degree of the first expansion valve (13) so that the refrigerant superheat degree at the outlet of the HC heat exchanger (14) becomes a predetermined value, and the third expansion valve control unit (73) The opening of the third expansion valve (18) is controlled so that the pressure difference between the refrigerant at the inlet and outlet of the unit (1C) is larger than a predetermined value. Therefore, during the cooling operation, the opening degree of the first expansion valve (13) can be controlled according to the load fluctuation in the showcase of the HC unit (1B). Further, even when the opening of the first expansion valve (13) is adjusted to be small during the cooling operation and the evaporation pressure of the refrigerant in the HC heat exchanger (14) is excessively reduced, the third expansion valve control unit (73) By controlling the opening of the third expansion valve (18) by adjusting the amount of refrigerant flowing into the bypass pipe (26), the refrigerant pressure difference between the inlet and outlet of the cooling unit (1C) is more than a predetermined value. Can also be adjusted to be larger. Accordingly, even during the cooling operation, the refrigerant can smoothly flow into the cooling unit (1C), and the refrigeration cycle can be smoothly performed in the refrigerant circuit (10).

  Moreover, according to this refrigeration apparatus (1), the 1st expansion valve control part (71) controls a 1st expansion valve (13) to a full open state at the time of heating and cooling operation, and an external heat exchanger (12) The refrigerant having a relatively high temperature that flows out of the refrigerant and is not decompressed flows into the HC heat exchanger (14), so that the HC heat exchanger (14) can easily function as a radiator. At the same time, the amount of refrigerant passing through the HC heat exchanger (14) is adjusted by controlling the opening of the third expansion valve (18) by the third expansion valve control unit (73), and the HC The temperature in the showcase of the unit (1B) can be adjusted to a predetermined temperature range.

  Further, according to the present refrigeration apparatus (1), since the bypass pipe (26) is provided, the refrigeration cycle can be performed in the refrigerant circuit (10) even when the first expansion valve (13) is fully closed. Can do. Therefore, the temperature control operation in the showcase of the HC unit (1B) is suspended by controlling the first expansion valve (13) to the fully closed state and the third expansion valve (18) to the fully open state. Can do.

  Further, according to the present refrigeration apparatus (1), the receiver (15) is provided with the injection pipe (27) for guiding the gas refrigerant in the receiver (15) to the intermediate pressure compression chamber of the compressor (11). The gas refrigerant flowing in can be sucked into the intermediate pressure compression chamber of the compressor (11) through the injection pipe (27). As a result, the superheated steam in the middle of compression in the compression chamber of the intermediate pressure of the compressor (11) can be cooled by the refrigerant from the injection pipe (27). Therefore, the compressor efficiency can be improved.

  Further, according to the present refrigeration apparatus (1), by providing the injection pipe (27), the refrigeration cycle can be performed in the refrigerant circuit (10) even when the second expansion valve (16) is fully closed. Can do. Therefore, the temperature control operation in the showcase of the cooling unit (1C) is suspended by controlling the second expansion valve (16) to the fully closed state and controlling the third expansion valve (18) to the fully closed state. be able to.

  In the first embodiment, in the first thermo-off operation, the opening degree of the third expansion valve (18) is controlled to be fully open, but the opening degree of the third expansion valve (18) is not necessarily fully open. It is not necessary to control the flow rate so that the refrigerant is smoothly circulated. The opening degree may be adjusted according to the amount of liquid in the receiver (15).

<< Embodiment 2 >>
As shown in FIG. 4, the refrigeration apparatus (1) of the second embodiment excludes the bypass pipe (26), the third expansion valve (18), and the injection pipe (27) from the refrigeration apparatus (1) of the first embodiment. Is.

  In the second embodiment, the controller (100) does not have the first thermo-off means (76) and the second thermo-off means (77) that the controller (100) of the first embodiment has. Further, the control means (70) does not include the third expansion valve control unit (73). Others are the same as in the first embodiment.

-Driving action-
In the refrigeration apparatus (1) of the second embodiment, the cooling operation and the heating / cooling operation are performed as in the first embodiment. However, since the first thermo-off means (76) and the second thermo-off means (77) are not provided, the first thermo-off operation and the second thermo-off operation cannot be performed as in the first embodiment. Hereinafter, each driving | operation operation | movement is explained in full detail.

<Cooling operation>
In the cooling operation, the first expansion valve controller (71) of the control means (70) is configured such that the external heat exchanger (12) functions as a radiator in the refrigerant circuit (10) and the HC heat exchanger (14) and The refrigeration heat exchanger (17) is switched by controlling the opening of the first expansion valve (13) so that a refrigeration cycle is performed in which the evaporator functions as an evaporator.

  Specifically, the first expansion valve control unit (71) calculates the evaporation pressure of the refrigerant in the HC heat exchanger (14) from the detected value (evaporation temperature) of the first temperature sensor (84), and the evaporation pressure The opening of the first expansion valve (13) is controlled so that becomes a predetermined value (target intermediate pressure).

  The control by the second expansion valve control unit (72), the compressor control unit (74), and the external fan control unit (75) is the same as that in the cooling operation of the first embodiment, and thus the description thereof is omitted.

  Through the control as described above, the high-temperature and high-pressure gas refrigerant compressed in the compressor (11) flows into the external heat exchanger (12) through the discharge pipe (21). In the external heat exchanger (12), the refrigerant radiates heat to the external air. Then, the refrigerant flows into the HC unit (1B) through the liquid pipe (22).

  In the HC unit (1B), the refrigerant flows into the first expansion valve (13) and is decompressed by the first expansion valve (13) to become a low-temperature and low-pressure refrigerant. Then, it flows into the HC heat exchanger (14) and absorbs heat from the air in the showcase to evaporate in the HC heat exchanger (14). Thereby, the air in the showcase of the HC unit (1B) is cooled. And the gas refrigerant which flowed out from HC heat exchanger (14) flows into a receiver (15) via an inflow pipe (23).

  The refrigerant that has flowed into the receiver (15) through the inflow pipe (23) and the bypass pipe (26) is separated into gas and liquid in the receiver (15). Only the liquid refrigerant in the receiver (15) flows into the outflow pipe (24).

  As described above, the first expansion valve control unit (71) controls the first expansion valve (13) so that the refrigerant evaporation pressure in the HC heat exchanger (14) becomes a predetermined value (target intermediate pressure). The opening is controlled. That is, the refrigerant pressure at the inlet of the cooling unit (1C) is maintained at a predetermined value (target intermediate pressure). Therefore, the refrigerant smoothly flows into the cooling unit (1C) through the outflow pipe (24).

  The refrigerant flowing into the cooling unit (1C) is depressurized in the second expansion valve (16) to become a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant flows into the refrigeration heat exchanger (17), and absorbs heat from the air in the showcase and evaporates in the refrigeration heat exchanger (17). Thereby, the air in the showcase of the cooling unit (1C) is cooled.

  As described above, the second expansion valve controller (72) causes the second expansion valve so that the degree of superheat of the refrigerant flowing out of the refrigeration heat exchanger (17) becomes a predetermined value (for example, 5 ° C.). The opening degree of (16) is controlled. Therefore, all the refrigerant evaporates in the refrigeration heat exchanger (17) to become a gas refrigerant, and is sucked into the compressor (11) from the suction port via the gas pipe (25). Then, the refrigerant is compressed again in the compressor (11) and discharged to the discharge pipe (21).

  By repeating the above operation, the inside of the showcase of the HC unit (1B) and the inside of the showcase of the cooling unit (1C) are cooled.

<Heating / cooling operation>
In the heating / cooling operation, the first expansion valve control unit (71) of the control means (70) is configured such that the external heat exchanger (12) and the HC heat exchanger (14) function as a radiator in the refrigerant circuit (10). The refrigeration heat exchanger (17) is switched by controlling the opening degree of the first expansion valve (13) so that a refrigeration cycle in which the evaporator (17) functions as an evaporator is performed. Specifically, the opening degree of the first expansion valve (13) is controlled to a fully open state.

  The control by the second expansion valve control unit (72), the compressor control unit (74), and the external fan control unit (75) is the same as that in the first embodiment, and thus the description thereof is omitted.

  Through the control described above, the high-temperature and high-pressure gas refrigerant discharged from the compressor (11) flows through the external heat exchanger (12) in the same manner as in the cooling operation. In the external heat exchanger (12), the refrigerant radiates heat to the external air. Then, the refrigerant flows into the HC unit (1B) through the liquid pipe (22).

  In the HC unit (1B), the refrigerant flows into the HC heat exchanger (14) at a relatively high temperature without being reduced in pressure in the fully opened first expansion valve (13). The refrigerant radiates heat to the air in the showcase in the HC heat exchanger (14). Thereby, the air in the showcase of the HC unit (1B) is heated. Then, the refrigerant that has flowed out of the HC heat exchanger (14) flows into the receiver (15) through the inflow pipe (23).

  The refrigerant flowing into the receiver (15) is separated into gas and liquid at the receiver (15). Only the liquid refrigerant in the receiver (15) flows into the outflow pipe (24).

  The refrigerant that has flowed into the outflow pipe (24) flows into the cooling unit (1C) and is decompressed by the second expansion valve (16) to become a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant flows into the refrigeration heat exchanger (17), dissipates heat to the air in the showcase and evaporates in the refrigeration heat exchanger (17). Thereby, the air in the showcase of the cooling unit (1C) is cooled.

  As described above, the second expansion valve controller (72) causes the second expansion valve so that the degree of superheat of the refrigerant flowing out of the refrigeration heat exchanger (17) becomes a predetermined value (for example, 5 ° C.). The opening degree of (16) is controlled. Therefore, all the refrigerant evaporates in the refrigeration heat exchanger (17) to become a gas refrigerant, and is sucked into the compressor (11) from the suction port via the gas pipe (25). Then, the refrigerant is compressed again in the compressor (11) and discharged to the discharge pipe (21).

  By repeating the above operation, the inside of the showcase of the HC unit (1B) is heated, while the inside of the showcase of the cooling unit (1C) is cooled.

  As described above, the refrigeration apparatus (1) of Embodiment 2 also connects the HC unit (1B) and the cooling unit by connecting the outside unit (1A), the HC unit (1B), and the cooling unit (1C) in series. The cooling operation in which the inside of the showcase of (1C) is cooled and the heating / cooling operation in which the inside of the showcase of the HC unit (1B) is heated and the inside of the showcase of the cooling unit (1C) is cooled are simply HC. It can be switched by controlling the opening of the first expansion valve (13) of the unit (1B). Therefore, it is not necessary to use different flow paths and flow path switching means for switching between the cooling operation and the heating / cooling operation, and the configuration of the refrigerant circuit (10) can be facilitated. Therefore, according to the second embodiment, the refrigeration apparatus (1) including the hot and cold showcase for heating or cooling the inside of the cabinet can be easily configured.

  By the way, the refrigeration apparatus (1) of Embodiment 2 is also similar to Embodiment 1 in the compressor (11), the external heat exchanger (12), the first expansion valve (13), and the HC heat exchanger (14). The second expansion valve (16) and the refrigeration heat exchanger (17) are connected in series. Therefore, for example, when the opening degree of the first expansion valve (13) is controlled according to the load fluctuation in the showcase of the HC unit (1B) during the cooling operation, the evaporation pressure of the refrigerant in the HC heat exchanger (14) is increased. It fluctuates according to the load fluctuation in the showcase. Therefore, depending on the load in the showcase, the evaporation pressure of the HC heat exchanger (14) may be excessively reduced, and the pressure difference between the refrigerant at the inlet and outlet of the cooling unit (1C) may be reduced. In such a case, it becomes difficult for the refrigerant to flow into the cooling unit (1C), and the refrigeration cycle cannot be normally performed in the refrigerant circuit (10).

  However, in the refrigeration apparatus (1) of the second embodiment, during the cooling operation, the opening degree of the first expansion valve (13) is set so that the refrigerant evaporation pressure in the HC heat exchanger (14) becomes a predetermined value (target intermediate pressure). By controlling in this way, the pressure of the refrigerant at the inlet of the cooling unit (1C) becomes constant and does not decrease. Therefore, according to the refrigeration apparatus (1) of the second embodiment, the pressure difference between the refrigerant at the inlet and the outlet of the cooling unit (1C) can be kept so as not to be below a certain level. Accordingly, even during the cooling operation, the refrigerant can smoothly flow into the cooling unit (1C), and the refrigerant circuit (10) can smoothly perform the refrigeration cycle.

  Further, according to the refrigeration apparatus (1) of the second embodiment, during the heating / cooling operation, the first expansion valve (13) is controlled to the fully open state and flows out of the external heat exchanger (12) without being decompressed. By allowing the relatively high temperature refrigerant to flow into the HC heat exchanger (14), the HC heat exchanger (14) can easily function as a radiator.

<< Other Embodiments >>
The refrigeration apparatus according to the present invention may be one in which the injection pipe (27) and the second thermo-off means (77) are excluded from the refrigeration apparatus (1) of the first embodiment. In this case, the intermediate pressure sensor (87) of Embodiment 1 is provided in the vicinity of the inlet of the cooling unit (1C) of the outflow pipe (24).

  In the refrigeration apparatus (1), the cooling operation, the heating / cooling operation, and the first thermo-off operation can be performed in the same manner as in the first embodiment. However, the second thermo-off operation cannot be performed. And also with such a refrigeration apparatus (1), the refrigeration apparatus (1) provided with the hot and cold showcase which heats or cools the inside of a store | warehouse | chamber can be comprised easily.

  Further, the refrigeration apparatus according to the present invention may be the one obtained by adding the injection pipe (27) and the second thermo-off means (77) of the first embodiment to the refrigeration apparatus (1) of the second embodiment.

  In the refrigeration apparatus (1), the cooling operation and the heating / cooling operation can be performed in the same manner as in the second embodiment. Further, the second thermo-off operation can be performed as in the first embodiment, but the first thermo-off operation cannot be performed. And also with such a refrigeration apparatus (1), the refrigeration apparatus (1) provided with the hot and cold showcase which heats or cools the inside of a store | warehouse | chamber can be comprised easily.

  Furthermore, in each said embodiment, the 2nd utilization system | strain which concerns on this invention was comprised by the cooling unit (1C) provided with the refrigeration heat exchanger (17) which refrigerates the foodstuff etc. in a showcase. However, the 2nd utilization system may be constituted by the freezing unit provided with the heat exchanger for freezing which freezes food etc. in a showcase.

  Moreover, in each said embodiment, although the 1st utilization system and the 2nd utilization system which concern on this invention were each provided one each, multiple 1st utilization systems were provided and these were arrange | positioned in parallel It may be a thing. Further, a plurality of second usage systems may be provided, and these may be arranged in parallel. Furthermore, a plurality of first usage systems may be provided and arranged in parallel, and a plurality of second usage systems may be provided and arranged in parallel. In addition, the 1st utilization system said here has the 1st expansion valve (13) and HC heat exchanger (14) of the said HC unit (1B), Comprising: A bypass pipe (26) and a receiver (15 ) And the second utilization system refers to the one having the second expansion valve (16) of the cooling unit (1C) and the heat exchanger for refrigeration (17).

  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 relates to a refrigeration apparatus, and is particularly useful for a refrigeration apparatus including a so-called hot and cold showcase that performs switching between heating and cooling.

FIG. 1 is a refrigerant circuit diagram of the refrigeration apparatus according to the first embodiment. FIG. 2 is a refrigerant circuit diagram illustrating an operation during the first thermo-off operation of the refrigeration apparatus according to the first embodiment. FIG. 3 is a refrigerant circuit diagram illustrating the operation of the refrigeration apparatus according to Embodiment 1 during the second thermo-off operation. FIG. 4 is a refrigerant circuit diagram of the refrigeration apparatus according to Embodiment 2 of the present invention.

Explanation of symbols

1 Refrigeration equipment
1A External unit (heat source system)
1B HC unit (first use system)
1C cooling unit (second usage system)
10 Refrigerant circuit
11 Compressor
12 External heat exchanger (heat source side heat exchanger)
13 First expansion valve
14 HC heat exchanger (first use side heat exchanger)
15 Receiver
16 Second expansion valve
17 Heat exchanger for refrigeration (second use side heat exchanger)
18 Third expansion valve (control valve)
26 Bypass pipe (bypass)
27 Injection tube
71 1st expansion valve control part (1st expansion valve control means)
72 Second expansion valve controller
73 Third expansion valve control section (valve control means)
76 First thermo-off means
77 Second thermo-off means

Claims (7)

A heat source system (1A) having a compressor (11) and a heat source side heat exchanger (12), and a first usage system (1B) having a first expansion valve (13) and a first usage side heat exchanger (14) And a refrigerant circuit (10) to which a second expansion system (1C) having a second expansion valve (16) and a second utilization side heat exchanger (17) are connected,
The compressor (11), the heat source side heat exchanger (12), the first expansion valve (13), the first usage side heat exchanger (14), the second expansion valve (16), and the second usage side heat exchanger. (17) is connected in series,
A first operation in which the heat source side heat exchanger (12) functions as a radiator and the first usage side heat exchanger (14) and the second usage side heat exchanger (17) function as an evaporator; The refrigerant in the second operation in which the heat source side heat exchanger (12) and the first usage side heat exchanger (14) function as a radiator and the second usage side heat exchanger (17) functions as an evaporator. A refrigeration apparatus comprising first expansion valve control means (71) for controlling the opening of the first expansion valve (13) so that the circuit (10) is switched. In claim 1,
A refrigeration apparatus comprising a receiver (15) provided between the first use side heat exchanger (14) and the second expansion valve (16) of the refrigerant circuit (10). In claim 2,
The refrigerant circuit (10) is provided with a bypass passage (26) that bypasses the first expansion valve (13) and the first use side heat exchanger (14), and the bypass passage (26) is opened. A variable degree control valve (18) is provided,
The first expansion valve control means (71) controls the first expansion valve (13) so that the refrigerant superheat degree at the outlet of the first usage side heat exchanger (14) becomes a predetermined value during the first operation. While configured to control the opening and control the first expansion valve (13) to a fully open state during the second operation,
During the first operation, the opening of the control valve (18) is controlled so that the pressure difference between the refrigerant at the inlet and the outlet of the second usage system (1C) is larger than a predetermined value, and during the second operation, A refrigeration apparatus comprising valve control means (73) for controlling the opening of the control valve (18) so that the internal temperature of the first utilization system (1B) is in a predetermined temperature range. In claim 3,
The first expansion valve control means (71) controls the first expansion valve (13) to a fully closed state, and the valve control means (73) controls the control valve (18) to an open state. A first thermo-off means (76) for controlling the first expansion valve control means (71) and the valve control means (73) to stop the temperature control operation of the first utilization system (1B) is provided. Refrigeration equipment. In claim 3 or 4,
The refrigerant circuit (10) is connected to an injection pipe (27) for guiding the gas refrigerant in the receiver (15) to an intermediate pressure compression chamber of the compressor (11). . In claim 5,
During the first operation, the valve control means (73) controls the valve control means (73) so that the control valve (18) is fully closed, and the second expansion valve (16) is controlled. A refrigeration apparatus comprising a second thermo-off means (77) for controlling to a fully closed state and stopping the temperature control operation of the second utilization system (1C). In claim 1 or 2,
The first expansion valve control means (71) opens the first expansion valve (13) so that the evaporation pressure of the refrigerant in the first usage-side heat exchanger (14) becomes a predetermined value during the first operation. On the other hand, the refrigeration apparatus is configured to control the first expansion valve (13) to a fully opened state during the second operation.

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