TWI709723B - Refrigeration device and operation method of refrigeration device - Google Patents

Abstract

The problem of the present invention is to provide a refrigeration device, which can be free from the influence of the operating environment and can achieve sufficient temperature rise with simple control.

In order to solve the above-mentioned problems, the present invention provides a refrigeration device including: a compressor (1); a flow path selector (2) that selectively switches the refrigerant flow path to the first flow path (RA) or the second flow path ( RB); external heat exchanger (3); flow direction restricting portion (RK), which restricts the refrigerant flow direction relative to the external heat exchanger (3); receiver (4); and, internal heat exchanger (5). By selecting the first flow path (RA) for cooling operation, the external heat exchanger (3) is supplied with gaseous refrigerant from the compressor (1) and functions as a condenser, while the internal heat exchanger (5) is used The restriction of the flow direction restriction portion (RK) is supplied with liquid refrigerant from the external heat exchanger (3) via the receiver (4), and functions as an evaporator. By selecting the second flow path (RB), the heating operation is performed, so the internal heat exchanger (5) is supplied with gaseous refrigerant from the compressor (1) through the receiver (4), and functions as a condenser. The exchanger (3) is supplied with liquid refrigerant from the internal heat exchanger (5) by the restriction of the flow direction restricting part (RK), and functions as an evaporator.

Description

Refrigeration device and operation method of refrigeration device

The present invention relates to a freezing device and an operating method of the freezing device, and more particularly to a freezing device and an operating method of the freezing device that can perform heating operation.

As a refrigeration device, there is known a device that can perform not only a cooling operation but also a temperature-rising operation (see Patent Document 1).

A refrigerating device capable of heating operation is mounted on a refrigerating car, for example, to deliver food to convenience stores. In this refrigerated vehicle, the refrigerating device is placed, when the internal temperature set at the time of delivery is lower than the outdoor temperature, the interior is cooled, and when the set internal temperature is higher than the outdoor temperature, the temperature is raised .

In this way, the temperature in the warehouse can be maintained at a constant temperature throughout the year without being affected by the hot and cold conditions in the delivery area.

The refrigeration system described in Patent Document 1 directly introduces the gaseous refrigerant compressed and discharged by the compressor into the heat exchanger, and performs heating operation in a so-called "hot gas" method.

Generally, in the "hot gas" mode, liquid refrigerant will stay in the receiver of the refrigerant circuit during heating operation. Therefore, the amount of refrigerant circulating in the refrigerant circuit depends on the operating environment (including the heat load in the storage and the external environment, etc.) Can not be fully obtained, but there are cases where the temperature rise is insufficient.

Therefore, the refrigeration system described in Patent Document 1 is configured as follows in the "hot gas" method: the refrigerating device is retained in the receiver (receiver in Patent Document 1) according to need. The liquid refrigerant is supplied to the low pressure side of the refrigerant circuit.

[Advanced Technical Literature]

(Patent Document)

Patent Document 1: Japanese Patent Application Publication No. 2004-162998

However, in the refrigeration system described in Patent Document 1, the supply of liquid refrigerant to the low pressure side of the refrigerant circuit is performed based on the measurement result of the pressure sensor and the opening and closing operation of the valve. Therefore, complicated control is required.

In addition, the temperature rise in the storage is carried out by introducing the heat generated by the compressor into the storage, so when the operating environment is severe (for example, when the outside air temperature is significantly lower than the set temperature in the storage, etc.) If the heating capacity is insufficient, there is a possibility that sufficient heating cannot be implemented.

Therefore, there is a demand for a refrigerating device that is not affected by the operating environment and can perform sufficient temperature rise with simple control.

That is, the problem to be solved by the present invention is to provide a refrigerating device and an operating method of the refrigerating device, which can not be affected by the operating environment and can achieve sufficient temperature rise with simple control.

In order to solve the above-mentioned problems, the present invention has the following configurations and procedures.

(1) A refrigerating device that has a refrigerant circuit and can optionally perform cooling and heating in the storage. The refrigerating device is characterized in that the refrigerant circuit includes a compressor that compresses and discharges the refrigerant; a flow path selection unit , Which selectively switches the flow path of the refrigerant in the refrigerant circuit to any one of the first flow path and the second flow path; an external heat exchanger, which is arranged outside the refrigerator, between the refrigerant and the Heat exchange between the air outside the compartment; the flow direction restricting part, which corresponds to the selection of the aforementioned flow path selection part, restricts the flow direction of the refrigerant entering and exiting the aforementioned external heat exchanger; the receiver, which can be retained The aforementioned refrigerant; and, the internal heat exchanger, which is arranged in the aforementioned compartment and performs heat exchange between the aforementioned refrigerant and the air in the aforementioned compartment; wherein, it is constituted as follows: according to the aforementioned first step by the aforementioned flow path selection unit 1. The selection of the flow path is to supply the refrigerant in the gas phase discharged from the compressor to the external heat exchanger, and then the external heat exchanger functions as a condenser and is subject to the restriction of the flow direction restriction section For the internal heat exchanger, the refrigerant in the liquid phase is supplied from the external heat exchanger via the liquid receiver, and the internal heat exchanger functions as an evaporator to perform a cooling operation; and, according to the aforementioned The selection of the second flow path made by the flow path selection unit is supplied to the internal heat exchanger via the liquid receiver and supplied by the compressor The discharged refrigerant in the gas phase, then the internal heat exchanger functions as a condenser, and the external heat exchanger is supplied with the liquid phase from the internal heat exchanger in accordance with the restriction of the flow direction restriction section The refrigerant, then, the aforementioned external heat exchanger functions at least as an evaporator to perform heating operation.

(2) The refrigeration system according to (1), wherein, when the first flow path is selected, the flow direction of the liquid phase of the refrigerant flowing in the internal heat exchanger is different from that when the second flow path is selected. In the flow path, the flow direction of the refrigerant in the gas phase flowing in the internal heat exchanger is the same.

(3) The refrigeration system according to (1), wherein the flow direction restricting portion is composed of a plurality of check valves.

(4) The refrigeration system according to (2), wherein the flow direction restricting portion is composed of a plurality of check valves.

(5) The refrigeration system according to any one of (1) to (4), wherein the external heat exchanger includes a fan that sends outside air in a certain direction; and an upstream heat exchanger, It is located on the upstream side of the aforementioned certain direction; and, the downstream side heat exchanger, which is connected in series to the aforementioned upstream side heat exchanger and is located on the downstream side; and is configured as follows: in the aforementioned cooling operation, the aforementioned upstream side The heat exchanger and the downstream side heat exchanger function integrally as a condenser for condensing the refrigerant in the gas phase discharged from the compressor, and during the heating operation, The liquid phase refrigerant is supplied from the internal heat exchanger to the upstream side heat exchanger. The upstream side heat exchanger adjusts and secures the remaining liquid refrigerant, and supercools the supplied liquid phase refrigerant, It functions as a supercooling heat exchanger, and the downstream heat exchanger evaporates the supercooled liquid phase refrigerant to function as an evaporator.

(6) The refrigeration system according to (5), wherein the upstream side heat exchanger is a row of piping lines of a specific capacity, and M (M is an integer greater than or equal to 1) are arranged in parallel in the predetermined direction M rows of fin-tube heat exchangers are formed, and the M is the maximum value when the capacity of the upstream side heat exchanger is within a range that does not exceed the capacity of the liquid receiver.

(7) An operating method of a refrigerating device for selectively performing cooling and heating in the storage. The operating method of the refrigerating device is characterized in that: the refrigerant circuit of the refrigerating device is provided with: a compressor; a flow path selection unit, It selectively switches the flow path of the refrigerant to either the first flow path or the second flow path; the first heat exchanger; the flow direction restricting section, which controls the flow of the refrigerant entering and exiting the first heat exchanger The direction is restricted; the liquid receiver; and, the second exchanger; wherein the first heat exchanger is arranged outside the warehouse, and the second heat exchanger is arranged inside the warehouse, and the The first flow path is configured as a flow path: to the first heat exchanger, the refrigerant in the gas phase discharged from the compressor is supplied, and the first heat exchanger functions as a condenser, and according to the flow direction The restriction of the restriction section, for the aforementioned second heat exchanger, The refrigerant in the liquid phase is supplied from the first heat exchanger via the receiver, so that the second heat exchanger functions as an evaporator; the second flow path is made into the following flow path: The heat exchanger is supplied with the refrigerant in the gas phase discharged from the compressor via the receiver, so that the second heat exchanger functions as a condenser, and the second heat exchanger is restricted by the flow direction restricting portion. 1 Heat exchanger, the refrigerant in the liquid phase is supplied from the second heat exchanger to make the first heat exchanger function as an evaporator; when cooling in the storage is performed, the flow path selection unit selects the first 1 flow path, and when the temperature in the chamber is increased, the flow path selection unit selects the second flow path, and the operation is performed in this manner.

According to the present invention, the following effects can be obtained: it is not affected by the operating environment, and a sufficient temperature rise can be performed with simple control.

1‧‧‧Compressor

2‧‧‧Four-way valve

2a~2d‧‧‧Port

3‧‧‧External heat exchanger

3A‧‧‧The first external heat exchanger

3Aa, 3Ab‧‧‧Port

3B‧‧‧The second external heat exchanger

3Ba, 3Bb‧‧‧Port

3C‧‧‧Tube

3f‧‧‧Heat sink

4‧‧‧Liquid receiver

5. 25A, 25B‧‧‧Internal heat exchanger

6‧‧‧Accumulator

7, 12, 22A, 22B‧‧‧Expansion valve

8~10、14~16‧‧‧Check valve

11, 13, 21A, 21B, 23‧‧‧Solenoid valve

17‧‧‧Gas-liquid heat exchanger

31‧‧‧Control Department

32‧‧‧Input part

51, 51A, 51B‧‧‧Refrigeration equipment

C‧‧‧Freezer Truck

C1‧‧‧Library (container)

CV‧‧‧Internal space

D1~D4‧‧‧Branch

FM1, FM2, FM25A, FM25B‧‧‧Fan

LP1, LP2‧‧‧Parallel circuit

L1~L11‧‧‧Piping line

Na, Nb‧‧‧Number of paths

P1~P5‧‧‧Path

Qa, Qb‧‧‧Capacity

RA, RB‧‧‧Flow path

RK‧‧‧Circulation Direction Restriction Department

S‧‧‧Container

Fig. 1 is a refrigerant circuit diagram of the refrigerating apparatus 51 which is an embodiment of the refrigerating apparatus of the present invention.

Fig. 2 is a diagram for explaining the control system of the refrigerating device 51.

FIG. 3 is a diagram for explaining the control mode of the four-way valve 2, the solenoid valve 11, and the solenoid valve 13 in the refrigeration system 51.

FIG. 4 is a schematic cross-sectional view for explaining the external heat exchanger 3 in the refrigeration unit 51. As shown in FIG.

FIG. 5 is a first perspective view for explaining the external heat exchanger 3.

FIG. 6 is a second perspective view for explaining the external heat exchanger 3.

FIG. 7 is a diagram for explaining the path in the external heat exchanger 3.

Fig. 8 is a side view of the refrigerating vehicle C, which is an example of placing the refrigerating device 51.

Fig. 9 is a refrigerant circuit diagram for explaining the cooling operation of the refrigeration unit 51.

Fig. 10 is a refrigerant circuit diagram for explaining the temperature-raising operation of the refrigerating device 51.

FIG. 11 is a table for explaining the control performed by the control unit 31 in the refrigeration system 51.

Fig. 12 is a local refrigerant circuit diagram for explaining the main part of the refrigerant circuit in the refrigeration system 51A in Modification 1.

Fig. 13 is a partial refrigerant circuit diagram for explaining the main part of the refrigerant circuit in the refrigeration system 51B in Modification 2.

According to the refrigerating device 51 of the embodiment and its modification examples, the refrigerating device according to the embodiment of the present invention will be described with reference to Figs. 1 to 13.

[Example]

The configuration of the refrigerating device 51 is shown in Fig. 1 as the refrigerant circuit diagram and Fig. 2 showing the control system.

That is, the refrigerant circuit of the refrigeration device 51 has the following configuration: a compressor 1, a four-way valve 2, an external heat exchanger 3 including a fan FM1 driven by a motor, a receiver 4, a fan including a fan FM2 driven by a motor Internal heat exchanger 5, accumulator 6, solenoid valve 11, and solenoid valve 13.

The operations of the compressor 1, the four-way valve 2, the fan FM1, the fan FM2, the solenoid valve 11, and the solenoid valve 13 in the refrigerant circuit are controlled by the control unit 31.

The operation instruction given by the user is transmitted to the control unit 31 via the input unit 32.

The external heat exchanger 3 and the internal heat exchanger 5 are so-called fin and tube heat exchangers. In addition, the external heat exchanger 3 has a configuration in which a first external heat exchanger 3A and a second external heat exchanger 3B are connected in series on a refrigerant circuit. The details of this external heat exchanger 3 are described in detail below.

The refrigerant circuit of the refrigeration device 51 will be described in detail.

The port 2a of the compressor 1 and the four-way valve 2 is connected by a piping line L1.

The port 2b of the four-way valve 2 and the port 3Ba of the second external heat exchanger 3B in the external heat exchanger 3 are connected by a piping line L2.

The port 3Bb of the second external heat exchanger 3B and the port 3Ab of the first external heat exchanger 3A are connected via a parallel circuit LP1.

The parallel circuit LP1 has the following configuration: a piping line L3 and a piping line L4.

The piping line L3 is equipped with an expansion valve 7; and a check valve 8, which is connected in series to the expansion valve 7 on the side of the first external heat exchanger 3A, and is only allowed to go from the first external heat exchanger 3A The second external heat exchanger 3B circulates.

The piping line L4 is provided with a check valve 9 which allows only the flow from the second external heat exchanger 3B to the first external heat exchanger 3A.

The port 3Aa of the first external heat exchanger 3A and the receiver 4 are connected by a piping line L5.

On the piping line L5, a branch D1 and a branch D2 are provided in the middle. Between the branch portion D1 and the branch portion D2, a check valve 10 is arranged, and the check valve 10 allows only the flow from the first external heat exchanger 3A to the receiver 4.

The receiver 4 and the internal heat exchanger 5 are connected via a parallel circuit LP2. The parallel circuit LP2 has the following configuration: a piping line L6 and a piping line L7.

The piping line L6 is provided with a solenoid valve 11 and an expansion valve 12 connected in series to the solenoid valve 11 on the side of the internal heat exchanger 5.

A solenoid valve 13 is arranged on the piping line L7.

The internal heat exchanger 5 and the port 2d of the four-way valve 2 are connected by a piping line L8. On the piping line L8, a branch D3 and a branch D4 are provided in the middle. Between the branch part D3 and the branch part D4, a check valve 14 is arranged, and the check valve 14 only allows the flow from the internal heat exchanger 5 to the four-way valve 2.

The branch D3 in the piping line L8 and the branch D1 in the piping line L5 are connected by the piping line L9. A check valve 15 is provided on the piping line L9, and this check valve 15 allows only the flow from the branch portion D3 to the branch portion D1.

The branch D4 in the piping line L8 and the branch D2 in the piping line L5 are connected by the piping line L10. A check valve 16 is provided in the piping line L10, and this check valve 16 only allows flow from the branch part D4 to the branch part D2.

The four branch parts and the four check valves, that is, the branch parts D1 to D4, the check valve 10, and the check valves 14 to 16, constitute the flow direction restricting part RK.

The flow direction restricting portion RK corresponds to the flow path selection performed with the switching of the four-way valve 2 and restricts the flow direction of the refrigerant flowing in and out of the port 3Aa of the external heat exchanger 3. The details are described below.

The port 2c of the four-way valve 2 and the compressor 1 are connected via a piping line L11 via an accumulator 6.

Regarding this refrigerant circuit, the control unit 31 selectively controls so that the operation of the four-way valve 2 becomes either mode A or mode B.

For specific description with reference to Fig. 3, the mode A is the following mode: the port 2a and the port 2b are connected, and the port 2c and the port 2d are connected.

Mode B is the following mode: connect port 2a to port 2d, and connect port 2b to port 2c.

According to the four-way valve 2, in the mode A, the flow path RA is selected as the line through which the refrigerant flows (refer to the thick line in FIG. 9). Also, in the mode B, the flow path RB is selected (refer to the thick line in Fig. 10). That is, the four-way valve 2 functions as a flow path selection unit that selects a flow path through which the refrigerant flows in the refrigerant circuit.

In addition, the control unit 31 controls the solenoid valve 11 and the solenoid valve 13 to alternately open them. This control is carried out in conjunction with the action of the four-way valve 2.

Specifically, as shown in FIG. 3, in mode A, the solenoid valve 11 is opened and the solenoid valve 13 is closed. In mode B, the solenoid valve 11 is closed, and the solenoid valve 13 is opened.

Next, the details of the external heat exchanger 3 will be described with reference to FIGS. 4 to 7.

FIG. 4 is a schematic configuration diagram corresponding to the cross section of the external heat exchanger 3. Fig. 5 is a perspective view of the external appearance viewed diagonally from the lower left of the external heat exchanger 3, and Fig. 6 is a perspective view of the external appearance viewed diagonally from the lower right. FIG. 7 is a diagram for explaining the path (refrigerant piping line) inside the external heat exchanger 3.

The directions of up, down, left, right, front, and back shown in Figs. 4 to 6 are directions set appropriately for easy understanding, and are not limited to the manner of installation.

As described above, the external heat exchanger 3 is constructed in the form of a fin-tube heat exchanger.

As shown in FIG. 4, the pipe 3c as a pipeline has 4 rows in the front-rear direction in the cross section, and 14 stages in each row in the vertical direction. That is, if it is a fin-tube heat exchanger with M rows and N stages, M=4 and N=14.

The tubes 3c are arranged folded back at the left and right ends so as to be connected as shown by the thick lines in FIG. 4.

Among the four rows, one row on the frontmost side is included in the first external heat exchanger 3A, and three rows from the rear side are included in the second external heat exchanger 3B.

That is, the first external heat exchanger 3A has 1 row and 14 stages, and the second external heat exchanger 3B has 3 rows and 14 stages.

In the first external heat exchanger 3A, the 7-stage pipes on the upper side constitute a path P1 as one line, and the 7-stage pipes on the lower side constitute a path P2 as a single line.

In the second external heat exchanger 3B, 14 pipes 3c in 5 or 4 rows in each row on the upper side constitute a path P3 as one line, and 14 pipes in 5 or 4 rows in each row in the center. The pipes 3c of 3c constitute a path P4 as one line, and the pipes 3c of 5 or 4 steps in each row on the lower side constitute a path P5 with a total of 14 pipes 3c as a single line.

Na

Nb。 The number of paths Na of the first external heat exchanger 3A is 2 or more and the number of paths Nb of the second external heat exchanger is less than or equal to Nb. That is, 2

Na

Nb.

The external heat exchanger 3 of the refrigerating device 51 satisfies this relationship. As described above, the number of paths Na of the first external heat exchanger 3A is 2, and the number of paths Nb of the second external heat exchanger 3B is 3 or less.

In the first external heat exchanger 3A, the port 3Aa is branched and connected to one end of the path P1 and one end of the path P2. Port 3Ab is branched and connected to the other end of path P1 and the other end of path P2.

That is, as shown in FIG. 7, the path P1 and the path P2 are connected in parallel between the port 3Aa and the port 3Ab.

In the second external heat exchanger 3B, the ports 3Ba are branched into three, and they are respectively connected to one end of the paths P3 to P5. Port 3Bb is divided into three, and they are respectively connected to the other end side of paths P3 to P5.

That is, as shown in FIG. 7, the paths P3 to P5 are connected in parallel between the port 3Ba and the port 3Bb.

The smaller the number of paths Na in the first external heat exchanger 3A is, the larger the area occupied by one path is. Therefore, the first external heat exchanger 3A is likely to have significant surface temperature unevenness.

Therefore, if the number of paths Na is increased, the area occupied by one path will become smaller, and the unevenness of the overall surface temperature will be suppressed.

That is, from the viewpoint of suppressing unevenness in surface temperature, it is preferable to increase the number of paths Na.

On the other hand, when two or more paths are provided, the greater the number of paths Na, the lower the flow velocity of the refrigerant passing through the paths.

Therefore, in the design, the degree of unevenness of the surface temperature and the flow rate of the refrigerant are considered, and the number of paths Na is set so that the heat exchange function can be performed well.

For example, the number of paths Na of the first external heat exchanger 3A and the number of paths Nb of the second external heat exchanger 3B may be the same number (Na=Nb), wherein the second external heat exchanger 3B will be described later It functions as an evaporator during the temperature-raising operation, and it is more preferable that the number of paths Na of the first external heat exchanger 3A be equal to or less than the number of paths Nb of the second external heat exchanger 3B (Na<Nb).

Considering the length of the piping between port 3Ba and port 3Bb, the flow path area of the piping (piping inner diameter), the speed of the refrigerant flowing in the piping, etc., the number of paths Nb of the second external heat exchanger 3B is appropriately set so that It can make a good phase change of liquid refrigerant into gaseous refrigerant.

As shown in Figs. 5 and 6, a plurality of fins 3f are respectively provided across the first external heat exchanger 3A and the second external heat exchanger 3B. Therefore, between the first external heat exchanger 3A and the second external heat exchanger 3B, heat is transferred to each other via the fins 3f.

The first external heat exchanger 3A and the second external heat exchanger 3B are arranged side by side in the front-rear direction. Specifically, the first external heat exchanger 3A is arranged so as to be on the windward side with respect to the flow direction of the wind generated by the driving of the fan FM1. That is, the first external heat exchanger 3A is an upstream heat exchanger, and the second external heat exchanger 3B is a downstream heat exchanger.

The refrigerating device 51 described in detail above can be applied to various equipment and devices. For example, it is placed in a refrigerated car C.

Fig. 8 is a side view showing an example mounted on the refrigerating vehicle C, and a part of it is a cut surface.

The internal heat exchanger 5 is arranged in the internal space CV of the container C1 (hereinafter, also referred to as the warehouse C1) that should maintain a constant temperature in the refrigerated vehicle C Inside, it exchanges heat with the air in the internal space CV.

Outside of the container C1 (for example, above the driver's seat), an external heat exchanger 3 is arranged to exchange heat with outside air.

Other components are installed on the outside of the container C1, and the installation location is not limited.

For example, the compressor 1 and the accumulator 6 are housed in the housing S, and are installed under the vehicle body. The control unit 31 and the input unit 32 are installed near the driver's seat. In particular, the input unit 32 is arranged in a place where the driver can easily operate it.

The power source of the compressor 1 is, for example, a battery or an engine of the refrigerated vehicle C (both not shown).

Next, the operation operation of the refrigerating device 51 will be described mainly with reference to Figs. 3, 7, and 9 to 11 based on the state of being mounted on the refrigerating vehicle C.

The refrigeration device 51 selectively executes a plurality of modes of operation based on an instruction given by the user via the input unit 32, that is, cooling operation, heating operation, defrosting operation of the external heat exchanger 3, and internal heat exchange The defrosting operation of the device 5 makes the temperature in the storage C1 constant.

First, the cooling operation and the heating operation are explained.

Fig. 9 is a diagram for explaining the refrigerant circuit during the cooling operation. Fig. 10 is a diagram for explaining the refrigerant circuit during the heating operation. Fig. 11 is a table for explaining the control of the control unit 31 during each operation. In the refrigerant circuits of Figs. 9 and 10, the piping portion where the refrigerant flows is indicated by thick lines, and the direction of the refrigerant flow is indicated by thick arrows.

(Cooling operation)

As shown in Figure 11, during the cooling operation, the control unit 31 makes the four-way valve 2 In mode A, the solenoid valve 11 is in an open state, the solenoid valve 13 is in a closed state, and the fan FM1 and the fan FM2 are in operation.

In Fig. 9, the blowing directions generated by the fan FM1 and the fan FM2 during this cooling operation are indicated by arrows DR1 and DR2, respectively.

As shown in FIG. 9, under the control of the control unit 31, the high-pressure gaseous refrigerant discharged from the discharge port of the compressor 1 flows from the port 2a of the four-way valve 2 in the mode A through the port 2b into the piping line L2.

The gaseous refrigerant flowing into the piping line L2 is supplied from the port 3Ba to the second external heat exchanger 3B in the external heat exchanger 3, flows through any one of the paths P3 to P5, and then receives gas from the port 3Bb. It flows out in the form of liquid mixed refrigerant.

The gas-liquid mixed refrigerant flowing out from the port 3Bb passes through the check valve 9 and is supplied from the port 3Ab to the first external heat exchanger 3A, flows through any one of the path P1 and the path P2, and then flows out from the port 3Aa.

In the external heat exchanger 3, the fan FM1 is in an operating state under the control of the control unit 31, and the outside air flows in the direction of the arrow DR1 in Fig. 9.

In this state, in the external heat exchanger 3, the second external heat exchanger 3B and the first external heat exchanger 3A function as an integrated condenser. That is, the gaseous refrigerant radiates heat to the outside air and condenses, and flows into the piping line L5 from the port 3Aa in the form of a high-pressure liquid refrigerant.

Specifically, the refrigerant is in the gas phase at the inlet of the second external heat exchanger 3B, which is the port 3Ba. As the refrigerant in the gas phase (gas refrigerant) flows through the second external heat exchanger 3B, it exchanges heat with the outside air, part of the gas refrigerant is condensed (liquefied), and the ratio of the liquid refrigerant to the gas refrigerant increases.

In this way, at the outlet of the second external heat exchanger 3B, which is the port 3Bb, the refrigerant becomes a gas-liquid mixed refrigerant in which a liquid refrigerant and a gaseous refrigerant are mixed. Here, the ratio of the liquid refrigerant varies depending on the operating conditions.

Next, the gas-liquid mixed refrigerant flowing out from the port 3Bb flows into the first external heat exchanger 3A from the port 3Ab. With the first external heat exchanger 3A, the heat exchange between the refrigerant and the outside air is continued, and in the outlet port 3Aa, the refrigerant is almost completely liquid (liquid) under high pressure.

Since the refrigerant undergoes a phase change from the gas phase to the liquid phase in the external heat exchanger 3, the volume of the refrigerant is reduced.

In the external heat exchanger 3, the number of paths Na of the first external heat exchanger 3A through which the refrigerant with a higher liquid phase ratio circulates due to the decrease in volume is less than that of the second external heat exchanger 3A through which the refrigerant with a higher gas phase ratio circulates. The number of paths Nb of the external heat exchanger 3B. In this way, the refrigerant flowing in the first external heat exchanger 3A has a larger mass flow rate than when it circulates in the second external heat exchanger 3B, and the degree of subcooling of the refrigerant also increases.

The high-pressure liquid refrigerant flowing into the piping line L5 passes through the check valve 10 and enters the receiver 4.

In the receiver 4, the remaining amount of liquid refrigerant corresponding to the operating environment is retained.

For example, when the thermal load in the storage C1 is small, the amount of circulating refrigerant may be small, and a large amount of liquid refrigerant may be accumulated in the receiver 4. On the other hand, when the thermal load in the storage C1 is large, since the amount of circulating refrigerant needs to be large, the amount of liquid refrigerant stored in the receiver 4 becomes small.

The receiver 4 has the following structure: When a liquid refrigerant accumulates, the liquid The refrigerant flows out.

The solenoid valve 13 is closed and the solenoid valve 11 is opened under the control of the control unit 31. Therefore, the liquid refrigerant flowing out of the receiver 4 flows into the piping line L6.

That is, the liquid refrigerant flowing into the piping line L6 enters the expansion valve 12 through the solenoid valve 11.

In the expansion valve 12, the liquid refrigerant expands. In this way, the liquid refrigerant is reduced in pressure and temperature, and gasification is promoted, and it becomes a gas-liquid mixed refrigerant in which the gas phase and the liquid phase are mixed.

The gas-liquid mixed refrigerant flowing out of the expansion valve 12 flows into the internal heat exchanger 5.

In the internal heat exchanger 5, the fan FM2 is in an operating state under the control of the control unit 31, and causes the air in the compartment C1 to flow in the direction of the arrow DR2 in FIG. 9.

In this state, the gas-liquid mixed refrigerant exchanges heat with the air in the storage C1, obtains heat from the air in the storage C1, and is completely vaporized to become a gaseous refrigerant. That is, the internal heat exchanger 5 functions as an evaporator, so the inside of the library C1 is cooled.

The gaseous refrigerant flowing out of the internal heat exchanger 5 flows into the piping line L8.

In the piping line L8, since the pressure of the gaseous refrigerant at the branch D3 is lower than the pressure at the branch D1 of the piping line L5, it does not flow into the piping line L9, but passes through the check valve 14 to the four-way valve 2.

Since the four-way valve 2 becomes mode A under the control of the control unit 31, the gaseous refrigerant flows from the port 2d through the port 2c, and further flows through the accumulator 6 and returns to the pressure The suction port of the shrink machine 1.

(Heating operation)

As shown in FIG. 11, during the heating operation, the control unit 31 sets the four-way valve 2 to mode B, the solenoid valve 11 is in the closed state, the solenoid valve 13 is in the open state, and the fans FM1 and FM2 are in operation.

The blowing direction of the fan FM1 and the fan FM2 during the heating operation is the same as the cooling operation, and is a constant direction, and is indicated by an arrow DR3 and an arrow DR4 in Figure 10.

As shown in FIG. 10, under the control of the control unit 31, the high-pressure gas refrigerant discharged from the discharge port of the compressor 1 flows from the port 2a of the four-way valve 2 in the mode B through the port 2d and flows into the piping line L8. Then, the gaseous refrigerant flows into the piping line L10 from the branch D4, and enters the receiver 4.

In the receiver 4, the gaseous refrigerant squeezes out the liquid refrigerant accumulated in the previous cooling operation, and fills the receiver 4 quickly.

Therefore, the gaseous refrigerant flows out of the receiver 4 following the accumulated liquid refrigerant. According to the control of the control unit 31, the solenoid valve 13 is opened and the solenoid valve 11 is closed. Therefore, the gaseous refrigerant flowing out of the receiver 4 flows into the piping line L7 and then flows into the internal heat exchanger 5.

In the internal heat exchanger 5, as described above, the fan FM2 is in an operating state under the control of the control unit 31, and the air in the compartment C1 flows in the direction of the arrow DR4 in FIG. 10.

In this state, the gaseous refrigerant exchanges heat with the air in the storage C1, releases heat to the air in the storage C1, condenses, and substantially becomes a high-pressure liquid refrigerant. Therefore, the temperature in the library C1 is increased.

The refrigerant flowing out of the internal heat exchanger 5 contains a liquid refrigerant and also contains a gaseous refrigerant in an amount corresponding to the operating environment such as the heat load in the storage C1.

Since the pressure at the branch portion D3 is lower than the branch portion D4, the gas-liquid mixed refrigerant containing the liquid refrigerant and the gaseous refrigerant flows into the piping line L9. Then, it flows through the check valve 15 and flows into the first external heat exchanger 3A of the external heat exchanger 3 from the port 3Aa.

In the external heat exchanger 3, the fan FM1 is in an operating state under the control of the control unit 31, and the outside air flows in the direction of the arrow DR3 in Fig. 10. Therefore, the first external heat exchanger 3A is located on the upstream side of the flow of outside air with respect to the second external heat exchanger 3B.

In this state, the liquid refrigerant is cooled in the first external heat exchanger 3A, and the temperature drops. That is, the first external heat exchanger 3A functions as a subcooling heat exchanger for the liquid refrigerant.

The gaseous refrigerant flowing into the first external heat exchanger 3A together with the liquid refrigerant is cooled by this and almost all becomes the liquid refrigerant.

The supercooled liquid refrigerant flows out of the port 3Ab of the first external heat exchanger 3A, and flows into the piping line L3.

In the piping line L3, the liquid refrigerant passes through the check valve 8 and enters the expansion valve 7.

In the expansion valve 7, the liquid refrigerant expands. As a result, the liquid refrigerant is reduced in pressure and temperature, and gasification is promoted to become a gas-liquid mixed refrigerant in which the gas phase and the liquid phase are mixed.

The gas-liquid mixed refrigerant flowing out of the expansion valve 7 flows into the second reservoir from port 3Bb External heat exchanger 3B.

In the second external heat exchanger 3B, the gas-liquid mixed refrigerant flowing in from the port 3Bb obtains heat from the outside air to evaporate by heat exchange with the outside air, becomes a gaseous refrigerant, and flows into the piping line L2 from the port 3Ba. That is, the second external heat exchanger 3B functions as an evaporator.

The gaseous refrigerant flowing into the piping line L2 passes through the port 2b of the four-way valve 2 in the mode B, passes through the port 2c, flows through the accumulator 6 and returns to the suction port of the compressor 1.

In this warming operation, the refrigeration device 51 obtains the following effects.

The four-way valve is used to switch between the cooling operation and the heating operation. During the heating operation, the temperature is raised not only by the heat obtained by the compressor operation, but also by the heat obtained by the external heat exchanger from the outside air. Therefore, a higher temperature raising ability is obtained.

The switching between the cooling operation and the heating operation is performed only by switching between the four-way valve and the solenoid valve, and there is no need to perform control based on the measurement result of the pressure sensor or the like. Therefore, the control of the running action is simple.

In the second external heat exchanger 3B, the gas-liquid mixed refrigerant performs heat exchange to obtain heat from outside air, and becomes a low-pressure gas refrigerant.

In the external heat exchanger 3, a plurality of fins 3f are provided so as to straddle the first external heat exchanger 3A and the second external heat exchanger 3B. Therefore, in the first external heat exchanger 3A, part of the heat released by the liquid refrigerant is transferred to the fins 3f and moved to the second external heat exchanger as a phase change in the second external heat exchanger The heat of evaporation is used.

In this way, due to the evaporation of the liquid refrigerant in the second external heat exchanger It is promoted, and therefore, it is possible to prevent the liquid refrigerant from being sucked into the compressor, which is the so-called liquid hammer (liquid back) phenomenon.

Moreover, even when the operating environment is, for example, driving in a cold area, and snow accumulates on the heat sink 3f due to snowfall, the snow adhering to the heat sink 3f will be affected by the first external heat exchanger due to the heat sink 3f. The heat released by the heat exchange during the heating operation becomes warm and melts.

In addition, the portion of each fin 3f on the side of the second external heat exchanger 3B becomes warm due to the following reasons: the outside air heated by the heat exchange in the first external heat exchanger 3A, Circulate to the downstream side; and, the heat imparted to the fin 3f by heat exchange in the first external heat exchanger 3A is transferred to the downstream side of the fin 3f.

In this way, since all the fins 3f are warmed efficiently, it is extremely effective to prevent snow or frost on the fins 3f.

Therefore, the execution interval of the defrosting operation of the freezing device 51 becomes longer, and the operation efficiency is improved.

During this temperature-raising operation, no liquid refrigerant stays in the receiver 4. On the other hand, in accordance with the operating environment including the heat load in the storage C1, the amount of refrigerant circulation required by the refrigerant circuit changes.

Therefore, in the first external heat exchanger 3A of the refrigerating device 51, there are liquid refrigerant and gaseous refrigerant in an amount corresponding to the operating environment.

In other words, the first external heat exchanger 3A replaces the receiver 4 during the heating operation to adjust and secure the remaining liquid refrigerant so as to circulate the refrigerant in the refrigerant circuit with the most suitable operating environment.

In this way, the pressure on the high pressure side of the refrigerant circuit can be maintained high Value.

Therefore, the condensation temperature of the refrigerant in the internal heat exchanger 5 becomes higher, and the temperature raising ability improves.

The refrigerating device 51 uses the flow direction restricting portion RK or the like to make the direction of the refrigerant flowing in the internal heat exchanger 5 the same in the cooling operation and the temperature raising operation. In addition, the direction of the airflow generated by the operation of the fan FM2 is also the same in the cooling operation and the heating operation.

Also, as shown in Figures 9 and 10, the flow direction of the refrigerant in the internal heat exchanger 5 may be such that it faces the blowing direction (arrows DR2, DR4) from the downstream side to the upstream side (from Inflow from the downstream side and outflow from the upstream side).

Due to the above and other reasons, there is no significant difference between the heat exchange efficiency during the cooling operation and the heat exchange efficiency during the heating operation. In this way, the heat exchange efficiency is further improved.

In the cooling operation and the heating operation, the amount of refrigerant enclosed in the refrigerant circuit is the same. In other words, since the liquid refrigerant is not stored in the receiver 4 during the heating operation, the liquid refrigerant remaining in the receiver 4 during the cooling operation is transferred to the first external heat exchanger 3A during the heating operation. Internally adjust and ensure the amount of liquid refrigerant.

Specifically, the amount of liquid refrigerant in the first external heat exchanger 3A is adjusted by changing the vaporization amount of the liquid refrigerant (amount of gaseous refrigerant).

Qb)。 Regarding the adjustment function of the amount of liquid refrigerant in the first external heat exchanger 3A, based on experiments, the following conclusions have been obtained: It is preferable to set the liquid refrigerant capacity Qa of the first external heat exchanger 3A to not The value of the capacity Qb of the liquid refrigerant exceeding the receiver 4 (that is, Qa

Qb).

The adjustment setting of this capacity Qa is performed by, for example, increasing or decreasing the number of rows of tubes 3c in the first external heat exchanger 3A.

That is, the first external heat exchanger 3A of M rows and N stages is formed by making one row into a fixed structure with a specific capacity, and this fixed structure is arranged in parallel along the blowing direction of the fan FM1.

At this time, it is preferable to set the value of M to the maximum value in a range in which the capacity of the first external heat exchanger 3A does not exceed the capacity of the liquid receiver 4.

Next, the defrosting operation will be described.

(Defrosting operation of internal heat exchanger 5)

If the cooling operation is performed for a long time, the moisture contained in the air in the storage C1 may freeze into frost and adhere to the fins of the internal heat exchanger 5. Since frost on the radiating fins hinders heat exchange, the defrosting operation of the internal heat exchanger 5 is performed to defrost.

As shown in Fig. 11, this defrosting operation is different from the heating operation only in stopping the fan FM1 and the fan FM2.

(Defrosting operation of external heat exchanger 3)

If the heating operation is performed for a long time, the moisture contained in the outside air may freeze into frost and adhere to the fins 3f of the external heat exchanger 3.

As described above, in the refrigerating device 51, the accumulation of snow or frost on the fins 3f of the external heat exchanger 3 is extremely difficult to generate. However, when the refrigerated vehicle C is driven during snowfall, if the amount of snowfall is significantly greater, the space between the adjacent fins 3f on the windward side of the external heat exchanger 3 (the first external heat exchanger 3A side) It may also be blocked.

At this time, since the heat exchange is hindered, the defrosting operation of the external heat exchanger 3 is performed, and the snow melting and defrosting are performed on the fins 3f.

As shown in Figure 11, this defrosting operation is different from the cooling operation only in stopping the fan FM1 and the fan FM2.

The embodiment of the present invention is not limited to the above-mentioned configuration, and may be modified within the scope not departing from the gist of the present invention.

(Variation example 1)

Modification 1 is that in the refrigerant circuit of the refrigerating device 51 of the embodiment, a gas-liquid heat exchanger 17 for heat exchange is provided between the piping line L6 on the upstream side and the piping line L8 on the downstream side of the indoor heat exchanger 5 ( An example of refrigeration device 51A) (refer to Fig. 12). Fig. 12 is a partial circuit diagram mainly showing a part of the refrigerant circuit of the refrigerating device 51A that is different from the refrigerant circuit of the refrigerating device 51 (see Fig. 1).

The gas-liquid heat exchanger 17 is connected between the solenoid valve 11 and the expansion valve 12 with respect to the piping line L6. In addition, the pipe line L8 is connected between the internal heat exchanger 5 and the branch portion D3.

In the cooling operation of the refrigerating device 51A, the refrigerant circulates in the direction of the arrow in the piping portion indicated by the thick line shown in FIG. 12.

The liquid refrigerant that is about to enter the expansion valve 12 during the cooling operation is cooled by heat exchange with the gaseous refrigerant flowing out of the internal heat exchanger 5 in the gas-liquid heat exchanger 17, and the degree of supercooling increases.

In this way, since the heat exchange in the internal heat exchanger 5 is used, the heat obtained from the air in the library C1 increases, and therefore, the ability to cool the inside of the library C1 improve.

In addition, since the evaporation of the liquid refrigerant in the internal heat exchanger 5 can be further promoted, the occurrence of the liquid hammer phenomenon of the compressor 1 can be prevented.

On the other hand, during the heating operation, the liquid refrigerant does not circulate through the piping line L6 but circulates through the piping line L7, so the gas-liquid heat exchanger 17 does not work.

(Variation 2)

With respect to the refrigerating device 51, Modification 2 includes two or more indoor heat exchangers (refrigerating device 51B). Here, referring to Fig. 13, an example in which two internal heat exchangers 25A and 25B are provided will be described. Fig. 13 is a partial circuit diagram mainly showing a different part of the refrigerant circuit of the refrigerating device 51B from the refrigerant circuit of the refrigerating device 51 (see Fig. 1).

As shown in FIG. 13, the refrigeration unit 51B is connected in parallel between the receiver 4 and the branch portion D3, and the indoor heat exchanger 25A including the fan FM25A and the indoor heat exchanger 25B including the fan FM25B are connected in parallel.

The expansion valve 22A is connected to the upstream side (the receiver 4 side) of the internal heat exchanger 25A, and the expansion valve 22B is connected to the upstream side of the internal heat exchanger 25B.

The upstream sides of the expansion valves 22A and 22B merge into a single line, and are connected to the receiver 4 via the solenoid valve 23.

A solenoid valve 21A is provided between the internal heat exchanger 25A and the expansion valve 22A and between the liquid receiver 4.

A solenoid valve 21B is provided between the internal heat exchanger 25B and the expansion valve 22B and between the liquid receiver 4.

The downstream side of expansion valve 22A, 22B merges into a line, which is connected to the branch Department D3.

The operations of the fan FM25A and the fan FM25B, and the solenoid valve 21A and the solenoid valve 21B are controlled by the control unit 31.

This refrigerating device 51B is mounted, for example, in a refrigerating car equipped with two or more compartments that should maintain a constant temperature.

The internal heat exchanger 25A and the internal heat exchanger 25B are installed so as to cool and raise the temperature of the inside of the respective different compartments.

The number and positions of solenoid valves are not limited to the example shown in Fig. 13.

According to this modification 2, the open state and the closed state of the solenoid valves 21A, 21B, and 23 can be combined to independently cool or raise the temperature of two or more compartments. For example, it is possible to cool only a specific one or two or more specific storages, or cool all the storages.

Modification 1 and Modification 2 can be appropriately combined.

The flow direction restricting portion RK is not limited to being constituted by using a plurality of check valves, but depending on the use of check valves, the flow direction restricting portion RK can be constructed at a relatively low cost.

1‧‧‧Compressor

2‧‧‧Four-way valve

2a~2d‧‧‧Port

3‧‧‧External heat exchanger

3A‧‧‧The first external heat exchanger

3Aa, 3Ab‧‧‧Port

3B‧‧‧The second external heat exchanger

3Ba, 3Bb‧‧‧Port

4‧‧‧Liquid receiver

5‧‧‧Cool internal heat exchanger

6‧‧‧Accumulator

7, 12‧‧‧Expansion valve

8~10、14~16‧‧‧Check valve

11、13‧‧‧Solenoid valve

51‧‧‧Freezing device

D1~D4‧‧‧Branch

FM1, FM2‧‧‧Fan

LP1, LP2‧‧‧Parallel circuit

L1~L11‧‧‧Piping line

RK‧‧‧Circulation Direction Restriction Department

Claims (5)

A refrigerating device has a refrigerant circuit and can selectively perform cooling and heating in the storage. The refrigerating device is characterized in that the refrigerant circuit includes: a compressor that compresses and discharges the refrigerant; a flow path selection part The flow path of the refrigerant in the refrigerant circuit is selectively switched to any one of the two types of flow paths; an external heat exchanger, which is arranged outside the compartment, and heats between the refrigerant and the air outside the compartment Exchange; the flow direction restricting part, which corresponds to the selection of the aforementioned flow path selection part, restricts the flow direction of the refrigerant entering and exiting the aforementioned external heat exchanger; the receiver, which can retain the aforementioned refrigerant; the internal heat exchanger, It is arranged in the aforementioned compartment to exchange heat between the aforementioned refrigerant and the air in the aforementioned compartment; and, a parallel flow path, which is arranged between the aforementioned liquid receiver and the aforementioned internal heat exchanger; wherein, as follows The configuration: the parallel flow path is composed of an expansion valve flow path and a bypass flow path. The expansion valve flow path is provided with an expansion valve and a solenoid valve in series, and the bypass flow path bypasses the expansion valve. The valve and the aforementioned solenoid valve are equipped with a solenoid valve; according to the selection of one of the aforementioned two flow paths by the aforementioned flow path selection section, the solenoid valve of the expansion valve flow path is closed and the bypass flow path is opened. Solenoid valve, the refrigerant in the gas phase discharged from the compressor is supplied to the front In the external heat exchanger, since the external heat exchanger functions as a condenser, it flows out from the external heat exchanger as the refrigerant in the liquid phase, passes from the flow direction restricting portion, passes through the receiver, and passes through the expansion The solenoid valve of the valve flow path is supplied to the expansion valve, and is decompressed and supplied to the internal heat exchanger, and the internal heat exchanger functions as an evaporator to return the refrigerant to the flow direction restricting portion , To perform cooling operation; and, according to the selection of the other of the two types of flow paths made by the flow path selection section, open the solenoid valve of the expansion valve flow path and close the solenoid valve of the bypass flow path, by The refrigerant in the gas phase discharged from the compressor is supplied to the liquid receiver via the flow direction restricting portion, and is supplied to the internal heat exchanger via the solenoid valve of the bypass flow path, due to the internal heat The exchanger functions as a condenser and returns from the internal heat exchanger as the refrigerant in the liquid phase to the flow direction restricting portion and is supplied to the external heat exchanger, and the external heat exchanger at least serves as an evaporator It functions to perform heating operation; when one of the two flow paths is selected, the flow direction of the refrigerant in the liquid phase flowing in the internal heat exchanger is the same as when the two flow paths are selected In the other case, the flow direction of the refrigerant in the gas phase flowing in the internal heat exchanger is the same. The refrigeration system according to claim 1, wherein the flow direction restricting portion is composed of a plurality of check valves. The refrigeration device according to claim 1 or 2, wherein the external heat exchanger includes a fan that sends outside air in a certain direction; and the upstream heat exchanger is located on the upstream side of the certain direction. ; And, the downstream side A heat exchanger, which is connected in series to the upstream side heat exchanger and is located on the downstream side; and is configured as follows: in the cooling operation, the upstream side heat exchanger and the downstream side heat exchanger serve as The condenser for the refrigerant in the gas phase discharged from the machine to condense and function integrally. During the heating operation, the refrigerant in the liquid phase is supplied from the internal heat exchanger to the upstream heat exchanger, and the upstream heat The heat exchanger adjusts and secures the remaining liquid refrigerant, supercools the supplied liquid phase refrigerant, and functions as a supercooling heat exchanger, and the downstream heat exchanger makes the supercooled liquid phase supercooled The refrigerant evaporates and functions as an evaporator. The refrigeration system according to claim 3, wherein the upstream side heat exchanger is a row of piping lines of a specific capacity, and M rows of fin-and-tube heat exchangers are arranged in parallel in the predetermined direction. The aforementioned M is an integer greater than or equal to 1, and M is the maximum value when the capacity of the upstream heat exchanger is within a range that does not exceed the capacity of the receiver. An operating method of a refrigerating device for selectively performing cooling and heating in a storage. The operating method of the refrigerating device is characterized in that: the refrigerant circuit of the refrigerating device is provided with: a compressor; a refrigerant flow path selection unit, which The flow path of the refrigerant is selectively switched to any one of the two types of flow paths; an external heat exchanger; a flow direction restricting section, which restricts the flow direction of the refrigerant entering and leaving the aforementioned external heat exchanger; ; Exchanger in the library; And, a parallel flow path; wherein the aforementioned parallel flow path is made into a parallel configuration of an expansion valve flow path and a bypass flow path, the expansion valve flow path is provided with an expansion valve and a solenoid valve in series, and the bypass flow path is The solenoid valve is arranged to bypass the expansion valve and the solenoid valve; the external heat exchanger is arranged outside the warehouse, and the internal heat exchanger is arranged inside the warehouse, and the expansion valve flow is closed And open the solenoid valve of the bypass flow path, and make one of the two types of flow paths into the following flow path: To the external heat exchanger, supply the gas phase discharged by the compressor The refrigerant makes the external heat exchanger function as a condenser, and from the external heat exchanger, according to the flow direction restricting portion, passes through the receiver, and through the solenoid valve of the expansion valve flow path to the The expansion valve in the expansion valve flow path supplies the refrigerant in the liquid phase, and the refrigerant is decompressed in the expansion valve and then supplied to the internal heat exchanger, so that the internal heat exchanger functions as an evaporator and returns To the flow direction restriction part; open the solenoid valve of the expansion valve flow path and close the solenoid valve of the bypass flow path, and make the other of the two types of flow paths the following flow path: For the internal heat exchanger , The refrigerant in the gas phase discharged from the compressor is supplied to the liquid receiver through the flow direction restricting portion, and supplied from the liquid receiver to the internal heat via the solenoid valve of the bypass flow path The exchanger makes the internal heat exchanger function as a condenser, and the refrigerant in the liquid phase is returned from the internal heat exchanger to the flow direction restricting portion, and the external heat exchanger functions as an evaporator Function; to make the flow direction of the refrigerant flowing in the liquid phase in the internal heat exchanger when one of the two flow paths is selected, and when the other one of the two flow paths is selected The flow direction of the refrigerant in the gas phase in the internal heat exchanger is the same, and when cooling is performed, the refrigerant flow selection section selects one of the two types of flow paths, and when the temperature is increased, the refrigerant The flow path selection unit selects the other one of the aforementioned two types of flow paths and operates in this manner.

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