CN110307677B - Heat exchanger for refrigerating device and refrigerating device - Google Patents

Abstract

The invention provides a heat exchanger for a refrigerating device, which can prolong the execution interval of the required defrosting action without reducing the cooling capacity. In order to solve the above problem, a heat exchanger for a refrigeration apparatus includes: a1 st heat exchanger having a1 st refrigerant piping line; a2 nd heat exchanger having a2 nd refrigerant piping line connected in series to the 1 st refrigerant piping line and arranged in parallel with the 1 st heat exchanger; a plurality of heat dissipation fins spanning the piping connected to the 1 st refrigerant piping line and the 2 nd refrigerant piping line; and a blower for blowing air to the 1 st heat exchanger and the 2 nd heat exchanger. The plurality of fins are arranged in parallel and facing each other, the pipe of the 1 st refrigerant pipe line and the pipe of the 2 nd refrigerant pipe line are connected so as to orthogonally penetrate the plurality of fins, and the 1 st heat exchanger and the 2 nd heat exchanger are arranged in parallel so that the 1 st heat exchanger is on the upstream side of the air blow.

Description

Heat exchanger for refrigerating device and refrigerating device

The present application is a divisional application of an invention patent application having a priority date of 2014, 3/3 and 7/3/2014, 2015, 2/3 and an application number of 201510056319.0 entitled "heat exchanger for refrigeration apparatus and refrigeration apparatus".

Technical Field

The present invention relates to a heat exchanger for a refrigeration apparatus and a refrigeration apparatus, and more particularly, to a refrigeration apparatus capable of selectively performing a cooling operation and a heating operation, and a heat exchanger for a refrigeration apparatus used in the refrigeration apparatus.

Background

As a refrigerator car for delivering commodities to convenience stores and the like, a refrigerator car mounted with a refrigerating device capable of maintaining the goods loaded in a storage at an optimum temperature without being affected by outdoor temperature is put into practical use, and therefore, not only the storage can be cooled but also the temperature can be raised.

According to this refrigeration apparatus, the interior of the refrigerator is cooled when the outdoor temperature is higher than the maintenance temperature, that is, mainly in summer, and is warmed when the outdoor temperature is lower than the maintenance temperature, that is, mainly in winter.

Patent document 1 describes an example of such a refrigeration apparatus as a refrigeration apparatus for land transportation. The refrigerating apparatus for land transportation described in patent document 1 is a heat pump type.

In general, if a freezer vehicle travels during snowfall, the outdoor heat exchanger may not function as a heat exchanger for temperature raising operation due to adhesion of blown snow. At this time, a defrosting (defrost) operation is performed to melt the attached snow.

However, if the defrosting operation is frequently performed, that is, if the interval of performing the defrosting operation becomes short, the efficiency of the temperature increasing operation is lowered.

Therefore, the refrigerating apparatus for road transportation described in patent document 1 has a structure that prevents the interval of execution of the defrosting operation from becoming short in the temperature rise mode operation during the traveling of the refrigerating vehicle during snowfall.

Specifically, the disclosed device is provided with: an air duct for guiding exhaust air of an engine of the refrigerator car to a suction side of the external heat exchanger; opening and closing means for the air passage in the air duct; and a Panel (Panel) disposed in front of the suction side of the outdoor heat exchanger so as to cover the outdoor heat exchanger.

For example, depending on the panel, snow will not blow directly into the off-bay heat exchanger. In this way, since the accumulated snow is suppressed and the function as the heat exchanger is maintained, it is no longer necessary to shorten the defrosting operation interval.

Prior art documents

(patent document)

Patent document 1: japanese laid-open patent application No. 2010-255909

Disclosure of Invention

Problems to be solved by the invention

However, in the refrigeration apparatus described in patent document 1, since the panel is disposed in front of the suction side of the outdoor heat exchanger so as to cover the outdoor heat exchanger, the traveling wind (wind generated when the vehicle travels, based on the relative velocity between the vehicle and the air) when the refrigeration vehicle travels is blocked by the panel and cannot be directly blown onto the outdoor heat exchanger.

Therefore, in the cooling operation in which the external heat exchanger functions as a condenser, there is a possibility that a sufficient air volume cannot be secured.

If a sufficient air volume cannot be ensured, the following problems occur: the refrigerant is not sufficiently condensed, and the cooling capacity is reduced.

Therefore, it is desirable for the heat exchanger for a refrigeration apparatus and the refrigeration apparatus to be able to extend the interval between required defrosting operations without reducing the cooling capacity.

Accordingly, an object of the present invention is to provide a heat exchanger for a refrigeration apparatus, which can extend the interval between required defrosting operations without reducing the cooling capacity, and a refrigeration apparatus using the same.

Means for solving the problems

In order to solve the above problem, the present invention has the following configuration.

(1) A heat exchanger for a refrigeration device is provided with:

a1 st heat exchanger having a1 st refrigerant piping line;

a2 nd heat exchanger having a2 nd refrigerant piping line connected in series to the 1 st refrigerant piping line, and arranged in parallel with the 1 st heat exchanger;

a plurality of heat sinks which cross over the piping connected to the 1 st refrigerant piping line and the 2 nd refrigerant piping line; and a process for the preparation of a coating,

a blower for blowing air to the 1 st heat exchanger and the 2 nd heat exchanger;

and the plurality of radiating fins are arranged in parallel and oppositely,

the pipe of the 1 st refrigerant pipe line and the pipe of the 2 nd refrigerant pipe line are connected to each other so as to orthogonally penetrate the plurality of fins,

the 1 st heat exchanger and the 2 nd heat exchanger are arranged in parallel such that the 1 st heat exchanger is on the upstream side of the air blowing by the air blower.

(2) The heat exchanger for a refrigerating apparatus as recited in (1), wherein the 1 st refrigerant piping line has two or more paths, and the number of the paths is Na (an integer of Na: 2 or more).

(3) The heat exchanger for a refrigerating apparatus as recited in (2), wherein the 2 nd refrigerant piping line has two or more paths, the number of the paths is Nb (an integer of Nb: 2 or more),

the number of paths Na and the number of paths Nb satisfy Na < Nb > 2.

(4) The heat exchanger for a refrigerating apparatus according to any one of (1) to (3), wherein at least one of the 1 st heat exchanger and the 2 nd heat exchanger is a fin-and-tube heat exchanger.

(5) The heat exchanger for a refrigerating apparatus according to any one of (1) to (3), wherein, when used as the outdoor heat exchanger of a refrigerating apparatus, the refrigerating apparatus is provided with a refrigerant circuit including the indoor heat exchanger and the outdoor heat exchanger, and selectively performs a cooling operation for cooling the inside of the refrigerating apparatus and a temperature raising operation for raising the temperature of the inside of the refrigerating apparatus,

in the cooling operation, the 1 st heat exchanger and the 2 nd heat exchanger function integrally as a condenser,

in the temperature raising operation, the 1 st heat exchanger functions as a subcooler and the 2 nd heat exchanger functions as an evaporator.

(6) The heat exchanger for a refrigerating apparatus according to (4), wherein when used as the outdoor heat exchanger of a refrigerating apparatus, the refrigerating apparatus is provided with a refrigerant circuit including an indoor heat exchanger and an outdoor heat exchanger, and selectively performs a cooling operation for cooling the inside of the refrigerator and a temperature raising operation for raising the temperature of the inside of the refrigerator,

in the cooling operation, the 1 st heat exchanger and the 2 nd heat exchanger function integrally as a condenser,

in the temperature raising operation, the 1 st heat exchanger functions as a subcooler and the 2 nd heat exchanger functions as an evaporator.

(7) A refrigeration apparatus provided with a refrigerant circuit including an interior heat exchanger, an exterior heat exchanger, and a liquid receiver capable of retaining a refrigerant, the refrigeration apparatus selectively performing a cooling operation for cooling the interior of the refrigeration apparatus and a heating operation for heating the interior of the refrigeration apparatus, the refrigeration apparatus characterized in that:

the outdoor heat exchanger is the heat exchanger for a refrigerating apparatus described in (1),

in the cooling operation, the 1 st heat exchanger and the 2 nd heat exchanger function integrally as a condenser,

in the temperature raising operation, the 1 st heat exchanger functions as a subcooler and the 2 nd heat exchanger functions as an evaporator,

the 1 st heat exchanger has a pipe array group in which M (an integer of M: 1 or more) pipe lines of a certain capacity are arranged in series in the air blowing direction, and M is a maximum value when the capacity of the 1 st heat exchanger is within a range not exceeding the capacity of the liquid receiver.

(8) The refrigeration system according to (7), wherein the 1 st refrigerant piping line has two or more paths, the number of paths being Na (an integer of Na: 2 or more),

the piping array group is provided corresponding to the two or more paths.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the following effects are obtained: the interval between required defrosting operations can be extended without reducing the cooling capacity.

Drawings

Fig. 1 is a refrigerant circuit diagram of an outdoor heat exchanger 3 as an example of a heat exchanger for a refrigeration apparatus and a refrigeration apparatus 51 using the outdoor heat exchanger 3 according to the present invention.

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

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

Fig. 4 is a schematic cross-sectional view for explaining the outdoor heat exchanger 3 in the refrigeration apparatus 51.

Fig. 5 is a perspective view 1 illustrating the external heat exchanger 3.

Fig. 6 is a perspective view 2 illustrating the outdoor heat exchanger 3.

Fig. 7 is a diagram illustrating a path in the outdoor heat exchanger 3.

Fig. 8 is a side view of a refrigerator car C illustrating an example of placement of the refrigerator 51.

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

Fig. 10 is a refrigerant circuit diagram for explaining the temperature increasing operation of the refrigerating apparatus 51.

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

Fig. 12 is a partial refrigerant circuit diagram for explaining a main part of a refrigerant circuit in a refrigeration apparatus 51A according to variation 1.

Fig. 13 is a partial refrigerant circuit diagram for explaining a main part of a refrigerant circuit in a refrigeration apparatus 51B according to a modification 2.

Fig. 14 is a refrigerant circuit diagram in a refrigerating apparatus 57 according to modification 3.

Fig. 15 is a diagram for explaining a control system of the freezing device 57.

Fig. 16 is a refrigerant circuit diagram for explaining a cooling operation of the refrigerating device 57.

Fig. 17 is a refrigerant circuit diagram for explaining the temperature increasing operation of the refrigerating device 57.

Fig. 18 is a table for explaining control performed by the control unit 31 in the refrigeration apparatus 57.

Fig. 19 is a diagram illustrating a parallel circuit LP1a according to variation 4.

Description of the reference numerals

1 compressor

2 four-way valve

2a-2d port

3 external heat exchanger

3A 1 st external heat exchanger

3Aa, 3Ab Port

3B No. 2 external heat exchanger

3Ba, 3Bb port

3C pipe

3f heat sink

3LA, 3LB refrigerant piping line

4 liquid receiver

5. 25A, 25B heat exchanger in storehouse

6 liquid accumulator

7. 12, 22A, 22B, 72 expansion valve

8-10, 14-16, 71, 73 check valve

11. 13, 21A, 21B, 23 solenoid valve

17 gas-liquid heat exchanger

31 control part

32 input unit

51. 51A, 51B, 57 freezer

C refrigeration vehicle

C1 warehouse (counter)

CV inner space

D1-D4 bifurcation part

G. GA1, GA2, GB3-GB5 piping array group

FM1, FM2, FM25A, FM25B fan (blower)

Parallel loop of LP1, LP2, LP72 and LP1A

L1-L11, 3LA, 3LB, L76, L77 piping lines

Number of Na and Nb paths

P1-P5 Path

Capacity of Qa, Qb

RA and RB channel

RK flow direction restriction

S container

Detailed Description

A heat exchanger for a refrigeration apparatus and a refrigeration apparatus according to embodiments of the present invention will be described with reference to fig. 1 to 19, based on an outdoor heat exchanger 3 of an embodiment, a refrigeration apparatus 51 using the outdoor heat exchanger 3, and a modification thereof.

(examples)

The structure of the refrigerating apparatus 51 is shown in fig. 1 as a refrigerant circuit diagram and fig. 2 showing a control system.

That is, the refrigerant circuit of the refrigeration apparatus 51 has the following structure: the system includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3 including a fan FM1 as a blower driven by a motor, a liquid receiver 4, an indoor heat exchanger 5 including a fan FM2 as a blower driven by a motor, a liquid accumulator 6, a solenoid valve 11, and a 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 controller 31.

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

The outside-house heat exchanger 3 and the inside-house heat exchanger 5 are so-called Fin and Tube heat exchangers. The outdoor heat exchanger 3 has the following structure: a1 st external heat exchanger 3A and a2 nd external heat exchanger 3B; and a circuit (parallel circuit LP1) connecting the 1 st outdoor heat exchanger 3A and the 2 nd outdoor heat exchanger 3B in series on the refrigerant circuit.

The 1 st outdoor heat exchanger 3A includes a refrigerant piping line 3LA, and the refrigerant piping line 3LA connects a port (port)3Aa to a port 3Ab (see fig. 4 and 7). The 2 nd outdoor heat exchanger 3B has a refrigerant piping line 3LB connecting the port 3Ba and the port 3Bb (see fig. 4 and 7). Details regarding this ex-warehouse heat exchanger 3 are detailed below.

The refrigerant circuit of the refrigerating apparatus 51 will be described in detail.

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

The port 2B of the four-way valve 2 and the port 3Ba of the 2 nd outdoor heat exchanger 3B of the outdoor heat exchangers 3 are connected by a piping line L2.

The port 3Bb of the 2 nd external heat exchanger 3B and the port 3Ab of the 1 st external heat exchanger 3A are connected via a parallel circuit LP 1.

The parallel circuit LP1 has the following structure: a pipe line L3 and a pipe line L4.

The piping line L3 includes: an expansion valve 7; and a check valve 8 connected in series to the expansion valve 7 on the 1 st outdoor heat exchanger 3A side and allowing flow only from the 1 st outdoor heat exchanger 3A to the 2 nd outdoor heat exchanger 3B.

A check valve 9 is disposed in the piping line L4, and the check valve 9 allows only the flow from the 2 nd external heat exchanger 3B to the 1 st external heat exchanger 3A.

The liquid receiver 4 is connected to the port 3Aa of the 1 st external heat exchanger 3A via a pipe line L5.

The pipe line L5 is provided with a branching portion D1 and a branching portion D2 at intermediate positions thereof. A check valve 10 is disposed between the branch portion D1 and the branch portion D2, and the check valve 10 allows only the flow from the 1 st outdoor heat exchanger 3A to the liquid receiver 4.

The liquid receiver 4 and the in-tank heat exchanger 5 are connected via a parallel circuit LP 2. The parallel circuit LP2 has the following structure: a pipe line L6 and a pipe line L7.

The piping line L6 includes: an electromagnetic valve 11; and an expansion valve 12 connected in series to the electromagnetic valve 11 on the side of the interior heat exchanger 5.

The solenoid valve 13 is disposed in the piping line L7.

The interior heat exchanger 5 is connected to a port 2d of the four-way valve 2 via a piping line L8. The pipe line L8 is provided with a branching portion D3 and a branching portion D4 at intermediate positions thereof. Between the branch portion D3 and the branch portion D4, a check valve 14 is disposed, and the check valve 14 allows only the flow from the interior heat exchanger 5 to the four-way valve 2.

The branch portion D3 of the pipe line L8 and the branch portion D1 of the pipe line L5 are connected by a pipe line L9. A check valve 15 is disposed in the piping line L9, and the check valve 15 allows only the flow from the branch portion D3 toward the branch portion D1.

The branch portion D4 of the pipe line L8 and the branch portion D2 of the pipe line L5 are connected by a pipe line L10. A check valve 16 is disposed in the piping line L10, and the check valve 16 allows flow only from the branch portion D4 toward the branch portion D2.

The four branches and the four check valves, i.e., the branches D1-D4, the check valve 10, and the check valves 14-16, constitute a flow direction restriction RK.

The flow direction regulating unit RK regulates the flow direction of the refrigerant flowing into and out of the port 3Aa of the exterior heat exchanger 3 in accordance with the selection of the flow path by switching the four-way valve 2. The details are as follows.

A port 2c of the four-way valve 2 is connected to the compressor 1 via a liquid accumulator 6 by a pipe line L11.

In this refrigerant circuit, the control unit 31 selectively controls the operation of the four-way valve 2 to be either one of the mode a and the mode B.

Specifically, referring to fig. 3, the mode a is the following mode: port 2a is connected to port 2b, and port 2c is connected to port 2 d.

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

In the four-way valve 2, in the mode a, the flow path RA is selected as a line through which the refrigerant flows (see a thick line in fig. 9). In mode B, the channel RB is selected (see 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 a refrigerant flows in the refrigerant circuit.

The controller 31 controls the solenoid valves 11 and 13 to be alternately opened. This control is performed in conjunction with the operation of the four-way valve 2.

Specifically, as shown in fig. 3, in the 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, details of the outdoor heat exchanger 3 will be described with reference to fig. 4 to 7.

Fig. 4 is a schematic configuration diagram corresponding to the cross section of the off-bank heat exchanger 3. Fig. 5 is an external perspective view of the outdoor heat exchanger 3 viewed obliquely from the lower left, and fig. 6 is an external perspective view of the outdoor heat exchanger 3 viewed obliquely from the lower right. Fig. 7 is a diagram for explaining the paths (refrigerant piping lines 3LA, 3LB) inside the exterior heat exchanger 3.

The respective directions of the upper, lower, left, right, front, and rear directions shown in fig. 4 to 6 are directions appropriately set for easy understanding, and are not limited to the installation pattern and the like.

As described above, the outdoor heat exchanger 3 is configured as a fin-and-tube heat exchanger.

As shown in fig. 4, the tubes 3c as the channels are 4 rows in the front-rear direction and 14 stages in the vertical direction in the cross section. That is, if the heat exchanger is a fin-and-tube heat exchanger having M rows and N stages, M is 4, and N is 14.

The tubes 3c are folded at both right and left ends and connected as shown by the thick lines in fig. 4.

Of the 4 rows, the 1 row on the forefront side is included in the 1 st bank-outside heat exchanger 3A, and the 3 rows from the rear side are included in the 2 nd bank-outside heat exchanger 3B.

That is, the 1 st bank-external heat exchanger 3A has 1 row and 14 stages, and the 2 nd bank-external heat exchanger 3B has 3 rows and 14 stages.

Here, 1 column or two or more columns connected in series are used as the piping column group G. For 1 column, it is also referred to as "piping column group" for convenience.

Therefore, the 1 st bank external heat exchanger 3A has a 1-row pipe row group GA with M equal to 1, and the 2 nd bank external heat exchanger 3B has a 3-row pipe row group GB with M equal to 3.

In the 1 st outdoor heat exchanger 3A, the upper 7-stage pipe 3cA constitutes the path P1 as one refrigerant piping line, and the lower 7-stage pipe constitutes the path P2 as one refrigerant piping line.

In the 2 nd external heat exchanger 3B, the upper row of 14 tubes 3cB, which is 5 or 4, constitutes the path P3 as one refrigerant piping line, the central row of 14 tubes 3cB, which is 5 or 4, constitutes the path P4 as one refrigerant piping line, and the lower row of 14 tubes 3cB, which is 5 or 4, constitutes the path P5 as one refrigerant piping line.

Therefore, as shown in fig. 4, in the 1 st outdoor heat exchanger 3A, the pipe array group GA1 and the pipe array group GA2 are provided in correspondence with the path P1 and the path P2, respectively. In the 2 nd outdoor heat exchanger 3B, pipe row groups GB3 to GB5 are provided corresponding to the paths P3 to P5, respectively.

The number Na of paths in the 1 st bank external heat exchanger 3A is an integer of 2 or more and is the number Nb (Nb: an integer of 2 or more) of paths in the 2 nd bank external heat exchanger. Namely, Na is more than or equal to 2 and less than or equal to Nb.

The outdoor heat exchanger 3 of the refrigeration apparatus 51 satisfies this relationship, and as described above, the number Na of paths of the 1 st outdoor heat exchanger 3A is 2, and the number Nb of paths of the 2 nd outdoor heat exchanger 3B is 3 or less.

In the 1 st outdoor heat exchanger 3A, the port 3Aa branches and connects one end of the path P1 and one end of the path P2. The port 3Ab branches and connects the other end of the path P1 and the other end of the path P2.

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

As shown in fig. 4, the route P1 and the route P2 are arranged as follows: the regions do not overlap each other in the air blowing direction (front-rear direction), and are substantially independent on the suction surface.

In the 2 nd outdoor heat exchanger 3B, the port 3Ba is branched into three and connected to one end side of the paths P3 to P5. The port 3Bb is branched into three ports and connected to the other end sides of the paths P3 to P5, respectively.

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

As shown in FIG. 4, the paths P3-P5 are configured in the following manner: the regions do not substantially overlap each other in the air blowing direction (front-rear direction), but are substantially independent on one surface on the suction side (hereinafter, also referred to as a suction surface).

Since the 1 st external heat exchanger 3A occupies a larger area on the suction surface as the number Na of paths is smaller, the 1 st external heat exchanger 3A is likely to have a significant surface temperature unevenness.

Therefore, if the number of paths Na is increased, the area occupied by one path on the suction surface becomes small, and the variation in the entire surface temperature is suppressed.

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

On the other hand, in the case where two or more paths are provided, the flow velocity of the refrigerant passing through the paths decreases as the number Na of paths increases.

Therefore, in view of design, the number Na of paths is set so that the heat exchange function is satisfactorily exhibited, taking into consideration the degree of unevenness in the surface temperature and the flow velocity of the refrigerant.

For example, the number of paths Na of the 1 st bank external heat exchanger 3A may be equal to the number of paths Nb of the 2 nd bank external heat exchanger 3B (Na ═ Nb), and the 2 nd bank external heat exchanger 3B may function as an evaporator in the temperature raising operation described later, and more preferably, the number of paths Na of the 1 st bank external heat exchanger 3A may be equal to or less than the number of paths Nb of the 2 nd bank external heat exchanger 3B (Na < Nb).

The number Nb of the paths of the 2 nd outdoor heat exchanger 3B is appropriately set so that the liquid refrigerant can be favorably changed into the gas refrigerant, in consideration of the length of the piping between the port 3Ba and the port 3Bb, the flow path area (piping inner diameter) of the piping, the speed of the refrigerant flowing in the piping, and the like.

As shown in fig. 5 and 6, the plurality of fins 3f are provided across the 1 st external heat exchanger 3A and the 2 nd external heat exchanger 3B, respectively.

Specifically, the plurality of fins 3f are arranged in parallel facing each other in close proximity to each other. Further, a pipe 3cA (see fig. 4) as a pipe of the refrigerant piping line of the 1 st bank exterior heat exchanger 3A and a pipe 3cB (see fig. 4) as a pipe of the refrigerant piping line of the 2 nd bank exterior heat exchanger 3B are connected to each other so as to orthogonally penetrate the plurality of fins 3 f.

Therefore, heat is mutually transferred between the 1 st external heat exchanger 3A and the 2 nd external heat exchanger 3B via the fins 3 f.

The 1 st external heat exchanger 3A and the 2 nd external heat exchanger 3B are arranged in parallel in the front-rear direction. In detail, the 1 st external heat exchanger 3A is configured as follows: the air flow direction is windward with respect to the air flow direction generated by the driving of fan FM 1. That is, the 1 st external heat exchanger 3A is an upstream side heat exchanger, and the 2 nd external heat exchanger 3B is a downstream side heat exchanger.

The refrigerating apparatus 51 described in detail above can be applied to various devices and apparatuses. For example, the vehicle is placed on a refrigerator car C.

Fig. 8 is a side view showing an example of the refrigerator car C placed thereon, and a part of the side view is a cut surface.

The interior heat exchanger 5 is disposed in the interior space CV of a container C1 (hereinafter, also simply referred to as "container C1") as a container to be kept at a constant temperature in the refrigerator car C, and exchanges heat with the air in the interior space CV.

The outside heat exchanger 3 is disposed outside the container C1 (for example, above the driver's seat) and exchanges heat with outside air.

The other members are disposed outside the tank C1, and the position of the disposition is not limited.

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

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

Next, the operation of the refrigeration apparatus 51 will be described with reference to fig. 3, 7, and 9 to 11, based on the state of being mounted on the refrigeration vehicle C.

The refrigeration apparatus 51 selectively executes a plurality of modes of operation, that is, a cooling operation, a temperature increasing operation, a defrosting operation of the exterior heat exchanger 3, and a defrosting operation of the interior heat exchanger 5, so that the temperature in the room C1 becomes a constant temperature, based on an instruction given by a user via the input unit 32.

First, the cooling operation and the temperature increasing operation will be described.

Fig. 9 is a diagram for explaining a refrigerant circuit in the cooling operation. Fig. 10 is a diagram for explaining a refrigerant circuit during the temperature raising operation. Fig. 11 is a table for explaining the control of the control unit 31 in each operation. In the refrigerant circuits of fig. 9 and 10, piping portions where the refrigerant flows are shown by thick lines, and the flow direction of the refrigerant is shown by thick arrows.

(Cooling operation)

As shown in fig. 11, during the cooling operation, the control unit 31 sets the four-way valve 2 to the mode a, the solenoid valve 11 to the open state, the solenoid valve 13 to the closed state, and the fan FM1 and the fan FM2 to the operating state.

In fig. 9, the blowing directions generated by the fan FM1 and the fan FM2 during the cooling operation are respectively shown by arrow DR1 and arrow DR 2.

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

The gaseous refrigerant flowing into the piping line L2 is supplied from the port 3Ba to the 2 nd outdoor heat exchanger 3B of the outdoor heat exchangers 3, flows through any one of the paths P3 to P5, and then flows out from the port 3Bb as a gas-liquid mixed refrigerant.

The gas-liquid mixed refrigerant flowing out of the port 3Bb is supplied from the port 3Ab to the 1 st outdoor heat exchanger 3A through the check valve 9, flows through any one of the paths P1 and P2, and then flows out of the port 3 Aa.

In the outdoor heat exchanger 3, the fan FM1 is in operation under the control of the controller 31, and outside air flows in the direction of arrow DR1 in fig. 9.

In this state, in the external heat exchanger 3, the 2 nd external heat exchanger 3B and the 1 st external heat exchanger 3A function as an integrated condenser. That is, the gaseous refrigerant radiates heat to the outside air and condenses, and flows as a high-pressure liquid refrigerant from the port 3Aa into the piping line L5.

Specifically, the refrigerant is entirely in a gas phase at the inlet port 3Ba of the No. 2 external heat exchanger 3B. The gas-phase refrigerant (gaseous refrigerant) flows through the 2 nd outdoor heat exchanger 3B, exchanges heat with the outside air, and a part of the gaseous refrigerant is condensed (liquefied), thereby increasing the ratio of the liquid refrigerant to the gaseous refrigerant.

Thus, the refrigerant becomes a gas-liquid mixed refrigerant in which the liquid refrigerant and the gaseous refrigerant are mixed together at the port 3Bb that is the outlet of the 2 nd outdoor heat exchanger 3B. Here, the ratio of the liquid refrigerant varies depending on the operating conditions.

Subsequently, the gas-liquid mixed refrigerant flowing out of the port 3Bb flows into the 1 st outdoor heat exchanger 3A from the port 3 Ab. The heat exchange between the refrigerant and the outside air is continued by the 1 st outdoor heat exchanger 3A, and substantially all of the refrigerant becomes a liquid phase (liquid state) under high pressure in the port 3Aa, which is the outlet.

The refrigerant changes its phase from a gas phase to a liquid phase in the exterior heat exchanger 3, and the volume of the refrigerant is reduced.

In the bank-exterior heat exchanger 3, the number Na of paths of the 1 st bank-exterior heat exchanger 3A through which the refrigerant having a high liquid phase ratio flows due to a decrease in volume is smaller than the number Nb of paths of the 2 nd bank-exterior heat exchanger 3B through which the refrigerant having a high gas phase ratio flows. Thus, the refrigerant flowing through the 1 st outdoor heat exchanger 3A has a larger mass flow rate and a larger degree of supercooling than the refrigerant flowing through the 2 nd outdoor heat exchanger 3B as a liquid refrigerant.

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

The liquid receiver 4 retains a remaining amount of liquid refrigerant corresponding to the operating environment.

For example, when the heat load in the tank C1 is small, the amount of the circulating refrigerant may be small, and a large amount of the liquid refrigerant may be accumulated in the liquid receiver 4. On the other hand, when the heat load in the tank C1 is large, the amount of the liquid refrigerant accumulated in the liquid receiver 4 becomes small because a large amount of the circulating refrigerant is required.

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

Since the electromagnetic valve 13 is closed and the electromagnetic valve 11 is opened under the control of the controller 31, the liquid refrigerant flowing out of the liquid receiver 4 flows into the pipe line L6.

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

In the expansion valve 12, the liquid refrigerant expands. As a result, the liquid refrigerant is reduced in pressure and temperature, and vaporization is promoted, so that the liquid refrigerant becomes a gas-liquid mixed refrigerant in which a gas phase and a liquid phase are mixed.

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

In the indoor heat exchanger 5, the fan FM2 is in operation under the control of the controller 31, and the air in the cabin C1 flows in the direction of arrow DR2 in fig. 9.

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

The gas refrigerant flowing out of the interior heat exchanger 5 flows into the piping line L8.

In the pipe line L8, the pressure of the gaseous refrigerant in the branch portion D3 is lower than the pressure of the branch portion D1 in the pipe line L5, and therefore the gaseous refrigerant does not flow into the pipe line L9 but reaches the four-way valve 2 through the check valve 14.

Since the four-way valve 2 is set to the mode a by the control of the controller 31, the gaseous refrigerant flows from the port 2d to the port 2c, further flows through the accumulator 6, and returns to the suction port of the compressor 1.

(operation at elevated temperature)

As shown in fig. 11, during the temperature raising operation, the control unit 31 sets the four-way valve 2 to the mode B, the solenoid valve 11 to the closed state, the solenoid valve 13 to the open state, and the fans FM1 and FM2 to the operating state.

The blowing directions of the fan FM1 and the fan FM2 during the temperature raising operation are the same as those of the cooling operation, and are respectively shown by arrows DR3 and DR4 in fig. 10.

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

In the liquid receiver 4, the liquid refrigerant accumulated in the previous cooling operation is pushed out by the gaseous refrigerant, and the liquid receiver 4 is quickly filled with the gaseous refrigerant.

Therefore, the gaseous refrigerant flows out of the liquid receiver 4 together with the accumulated liquid refrigerant. Since the electromagnetic valve 13 is opened and the electromagnetic valve 11 is closed under the control of the controller 31, the gaseous refrigerant flowing out of the liquid receiver 4 flows into the piping line L7 and then flows into the interior heat exchanger 5.

In the indoor heat exchanger 5, as described above, the fan FM2 is in an operating state under the control of the controller 31, and the air in the warehouse C1 flows in the direction of arrow DR4 in fig. 10.

In this state, the gas refrigerant exchanges heat with the air in the bank C1, releases heat to the air in the bank C1, condenses, and becomes a substantially high-pressure liquid refrigerant. Therefore, the temperature in the bank C1 increases.

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

Since the pressure at the branch portion D3 is lower than that at the branch portion D4, the gas-liquid mixed refrigerant including the liquid refrigerant and the gaseous refrigerant flows into the piping line L9. Then, the fluid flows through the check valve 15 and flows into the 1 st outdoor heat exchanger 3A of the outdoor heat exchangers 3 from the port 3 Aa.

In the outdoor heat exchanger 3, the fan FM1 is in operation under the control of the controller 31, and outside air flows in the direction of arrow DR3 in fig. 10. Therefore, the 1 st outdoor heat exchanger 3A is located on the upstream side of the 2 nd outdoor heat exchanger 3B through which the outside air flows.

In this state, the liquid refrigerant is cooled and the temperature is lowered in the 1 st outdoor heat exchanger 3A. That is, the 1 st outdoor heat exchanger 3A functions as a supercooling heat exchanger for the liquid refrigerant.

The gaseous refrigerant flowing into the 1 st outdoor heat exchanger 3A together with the liquid refrigerant is cooled by the gaseous refrigerant, and substantially all of the gaseous refrigerant becomes liquid refrigerant.

The supercooled liquid refrigerant flows out of the port 3Ab of the 1 st outdoor heat exchanger 3A and flows into the pipe line L3.

In the pipe 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. Thus, the liquid refrigerant is reduced in pressure and temperature, and the vaporization is promoted, so that the liquid refrigerant becomes a gas-liquid mixed refrigerant in which a gas phase and a liquid phase are mixed.

The gas-liquid mixed refrigerant flowing out of the expansion valve 7 flows into the 2 nd outdoor heat exchanger 3B from the port 3 Bb.

In the 2 nd outdoor heat exchanger 3B, the gas-liquid mixed refrigerant flowing from the port 3Bb is evaporated by taking heat from the outside air by heat exchange with the outside air, turns into a gaseous refrigerant, and flows into the piping line L2 from the port 3 Ba. That is, the 2 nd external heat exchanger 3B functions as an evaporator.

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

In this temperature raising operation, the refrigerating apparatus 51 obtains the following effects.

Switching between the cooling operation and the temperature-raising operation is performed using the four-way valve, and in the temperature-raising operation, the temperature is raised not only by the heat obtained by the operation of the compressor but also by the heat obtained from the outside air by the external heat exchanger. Therefore, a higher temperature raising capability is obtained.

The switching between the cooling operation and the temperature increasing operation is performed only by switching between the four-way valve and the solenoid valve, and it is not necessary to perform control based on the measurement result of the pressure sensor or the like. Therefore, the control of the operation is simple.

In the 2 nd outdoor heat exchanger 3B, the gas-liquid mixed refrigerant undergoes heat exchange for taking out heat from the outside air, and becomes a low-pressure gaseous refrigerant.

In the external heat exchanger 3, a plurality of fins 3f are provided so as to straddle the 1 st and 2 nd external heat exchangers 3A and 3B. Therefore, in the 1 st external heat exchanger 3A, part of the heat released from the liquid refrigerant is transferred to the heat radiation fins 3f and transferred to the 2 nd external heat exchanger, and is used as the evaporation heat of the phase change in the 2 nd external heat exchanger.

In this way, since evaporation of the liquid refrigerant in the 2 nd outdoor heat exchanger is promoted, it is possible to prevent a so-called liquid strike (liquid return) phenomenon in which the liquid refrigerant is sucked into the compressor.

Even when snow is accumulated on the fins 3f due to snowfall in the case where the driving environment is, for example, driving in a cold district, the snow adhering to the fins 3f is warmed and melted by the heat released by the heat exchange performed by the 1 st outdoor heat exchanger in accordance with the temperature increasing operation.

Also, the portion of each fin 3f on the 2 nd external heat exchanger 3B side becomes warm due to the following reasons: the outside air whose temperature has been raised by the heat exchange in the 1 st outdoor heat exchanger 3A flows downstream; and, the heat applied to the fins 3f by the heat exchange in the 1 st external heat exchanger 3A is transferred to the downstream side of the fins 3 f.

In this way, since all the fins 3f are efficiently warmed, snow accumulation or frost formation on the fins 3f is extremely effectively prevented.

Therefore, the interval between the defrosting operations of the refrigerating apparatus 51 becomes longer, and the operation efficiency improves.

In this temperature raising operation, no liquid refrigerant remains in the liquid receiver 4. On the other hand, the refrigerant circulation amount required for the refrigerant circuit changes according to the operating environment including the heat load in the bank C1.

Therefore, the liquid refrigerant and the gaseous refrigerant in an amount corresponding to the operating environment exist in the 1 st outdoor heat exchanger 3A of the refrigeration apparatus 51.

In other words, the 1 st outdoor heat exchanger 3A adjusts and secures the remaining liquid refrigerant in the temperature raising operation in place of the liquid receiver 4 so that the refrigerant circuit circulates the refrigerant in an amount most suitable for the operating environment.

Thus, the pressure on the high-pressure side of the refrigerant circuit can be maintained at a high value.

Therefore, the refrigerant condensation temperature in the interior heat exchanger 5 becomes high, and the temperature raising capability is improved.

The refrigerating apparatus 51 makes the direction of the refrigerant flowing through the interior heat exchanger 5 the same during the cooling operation and the temperature increasing operation by using the flow direction regulating unit RK or the like. The airflow direction generated by the operation of fan FM2 is also the same in the cooling operation and the temperature increasing operation.

As shown in fig. 9 and 10, the refrigerant flowing direction in the interior heat exchanger 5 may be: the air flows from the downstream side to the upstream side (flows in from the downstream side and flows out from the upstream side) so as to face the air blowing direction (arrows DR2 and DR 4).

For the above reasons, no significant difference is generated between the heat exchange efficiency in the cooling operation and the heat exchange efficiency in the temperature raising operation. This further improves the heat exchange efficiency.

The amount of refrigerant sealed in the refrigerant circuit is the same between the cooling operation and the temperature increasing operation. That is, since the liquid refrigerant is not stored in the liquid receiver 4 during the temperature raising operation, the amount of the liquid refrigerant remaining in the liquid receiver 4 during the cooling operation is adjusted and secured in the 1 st external heat exchanger 3A during the temperature raising operation.

Specifically, the secured amount of the liquid refrigerant in the 1 st outdoor heat exchanger 3A is adjusted by changing the vaporization amount of the liquid refrigerant (the amount of the gaseous refrigerant).

With regard to the adjustment function of the liquid refrigerant amount in this 1 st outdoor heat exchanger 3A, the following conclusion is obtained by experiments: preferably, the capacity Qa of the liquid refrigerant in the 1 st outdoor heat exchanger 3A is set to a value not exceeding the capacity Qb of the liquid refrigerant in the liquid receiver 4 (i.e., Qa. ltoreq. Qb).

The adjustment setting of the capacity Qa is performed by, for example, increasing or decreasing the number of rows of the tubes 3c in the 1 st outdoor heat exchanger 3A.

That is, the 1 st outdoor heat exchanger 3A of M rows and N stages is formed by arranging M number of the standard structures in parallel along the blowing direction of the fan FM1, with one row having a specific capacity.

In this case, it is preferable that the value of M is a maximum value within a range in which the capacity of the 1 st external heat exchanger 3A does not exceed the capacity of the liquid receiver 4.

Next, the defrosting operation will be described.

(defrosting operation of the heat exchanger 5 in the interior)

If the cooling operation is performed for a long time, moisture contained in the air in the bank C1 may freeze and frost and adhere to the heat sinks of the in-bank heat exchanger 5. Since the frost on the fins hinders the heat exchange, the defrosting operation of the interior heat exchanger 5 is performed to remove the frost.

As shown in fig. 11, this defrosting operation differs from the temperature raising operation only in stopping the fan FM1 and the fan FM 2.

(defrosting operation of outdoor Heat exchanger 3)

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

As described above, in the refrigeration apparatus 51, snow or frost is extremely unlikely to be formed on the fins 3f of the outdoor heat exchanger 3. However, when the refrigerator car C is driven during snowfall, if the amount of snowfall is significantly large, the adjacent fins 3f on the upstream side (1 st bank-outside heat exchanger 3A side) of the bank-outside heat exchanger 3 may be clogged.

At this time, because heat exchange is inhibited, the defrosting operation of the exterior heat exchanger 3 is performed, and snow melting and defrosting are performed on the fins 3 f.

As shown in fig. 11, this defrosting operation differs from the cooling operation only in stopping the fan FM1 and the fan FM 2.

Specific parameters of the outdoor heat exchanger 3 are set as follows, for example:

thickness Ea in the front-rear direction of the 1 st external heat exchanger 3A (see fig. 5): 19.05mm

Thickness Eb in the front-rear direction of the No. 2 external heat exchanger 3B (see fig. 5): 57.15mm

Total thickness in front-rear direction (Ea + Eb): 76.20mm

Height Ec in the vertical direction (see fig. 5): 355.6mm

Effective width (width of ventilation portion) Ed in the left-right direction (see fig. 5): 1050mm

Refrigerant piping diameter (outer diameter): phi 9.53mm

Pitch Ee of refrigerant piping (see fig. 4): 25.4mm

(during cooling operation (the external heat exchanger 3 functions as a condenser))

Heat dissipation capacity: 4.8kW

Refrigerant flow rate in the refrigerant pipe: about 1.14kg/min

Flow rate of refrigerant in piping of the 1 st external heat exchanger 3A: 0.165m/s (liquid phase state)

Flow rate of refrigerant in piping of the No. 2 exterior heat exchanger 3B: 1.05m/s (gas phase state)

0.11 meter/second (m/s) (liquid phase state)

(during temperature-raising operation (the external heat exchanger 3 functions as at least an evaporator))

Heat absorption capacity: 2.5kW

Refrigerant flow rate in the refrigerant pipe: about 2.10kg/min

Flow rate of refrigerant in piping of the 1 st external heat exchanger 3A: 0.260m/s (liquid phase state)

Flow rate of refrigerant in piping of the No. 2 exterior heat exchanger 3B: 6.45m/s (gas phase state)

0.173m/s (liquid phase state)

Refrigerant temperature at the inlet of the 1 st outdoor heat exchanger 3A: 20 deg.C

Refrigerant temperature at the outlet of the 1 st outdoor heat exchanger 3A: 5 deg.C

The parameters of the external heat exchanger 3 are set to other specifications so as to obtain the heat radiation amount particularly in the cooling operation (4.8 kW in the above example).

As an example of the setting procedure, first, the 2 nd outdoor heat exchanger 3B functions as a condenser during the cooling operation and functions as an evaporator during the temperature raising operation, and therefore, in consideration of the parameters during the cooling operation and the parameters during the temperature raising operation, 3 rows (4 rows as condensers) of 14 stages of 3 paths are set (step "a").

Next, for example, Na < Nb, which is a more preferable condition of the number of paths, is used to set the path of the 1 st external heat exchanger 3A to 2. Further, the number of columns M is 1 calculated so that the maximum value of the capacity of the 1 st external heat exchanger 3A does not exceed the capacity of the liquid receiver 4.

In such a step, the specification is set to, for example, 1 column, 14 segments, and 2 paths (step "B").

As described above, when snow is accumulated on the fins 3f of the 1 st outdoor heat exchanger 3A, the outdoor heat exchanger 3 can melt the snow by the temperature increasing operation.

The 1 st reservoir external heat exchanger 3A is required only to release heat for melting snow, and the excess heat is consumed only to warm up melted water and is useless.

Further, since the accumulated snow covers the entire suction surface of the first outdoor heat exchanger 3A, it is preferable that the melted region is dispersed as much as possible on the entire suction surface, rather than being melted locally.

As shown in the parameter example, the difference between the refrigerant temperatures at the inlet and the outlet of the 1 st outdoor heat exchanger 3A is, for example, 15 ℃ (deg).

For example, if the number of passes Na is 1, the inlet is on the upper side, and the outlet is on the lower side, only the upper side is set to the highest temperature, and the lower side is set to the lowest temperature, and a gentle temperature gradient is generated in the vertical direction.

Therefore, when the melted region and the non-melted region are generated, the melted region and the non-melted region are divided into two parts in the vertical direction.

In contrast, the number Na of paths is set to 2, for example, as in the example, and the region substantially occupied by each path on the suction surface is separated into an upper side and a lower side. Further, an inlet of one path may be provided on the upper side, an outlet of the other path may be provided on the lower side, and the outlet of the upper path and the inlet of the lower path may be arranged at the central portion in the vertical direction.

At this time, since the temperature gradient in the vertical direction of the suction surface is "high-low-high-low" from the upper side toward the lower side, when there are melted regions and non-melted regions, "melted/non-melted/non-melted" occurs alternately 2 times. Therefore, the melted region is preferably dispersed.

This dispersion is more finely spread as the number of paths Na is larger, and is therefore preferable.

Further, the higher the number of paths Na, the less concentrated and dispersed the high temperature range. Therefore, it is preferable to suppress the emission of excessive heat for raising the temperature of the melted water.

Thus, the number of paths Na is preferably 2 or more.

The outdoor heat exchanger 3 and the refrigeration apparatus 51 of the embodiment are not limited to the above-described configurations, and modifications may be made without departing from the scope of the present invention.

(modification 1)

The modification 1 is an example in which a liquid-gas heat exchanger 17 (a refrigeration apparatus 51A) (see fig. 12) for performing heat exchange is provided in a refrigerant circuit of the refrigeration apparatus 51 between a pipe line L6 on the upstream side and a pipe line L8 on the downstream side of the indoor heat exchanger 5. Fig. 12 is a partial circuit diagram mainly showing a portion of the refrigerant circuit of the refrigeration apparatus 51A which is different from the refrigerant circuit of the refrigeration apparatus 51 (see fig. 1).

The liquid-gas heat exchanger 17 is connected between the solenoid valve 11 and the expansion valve 12 via a pipe line L6. The piping line L8 is connected between the interior heat exchanger 5 and the branch unit D3.

In the cooling operation of the refrigeration apparatus 51A, the refrigerant flows in the direction of the arrow in the piping portion indicated by the thick line shown in fig. 12.

Immediately before the liquid refrigerant entering the expansion valve 12 in the cooling operation is cooled by heat exchange with the gas refrigerant flowing out of the interior heat exchanger 5 in the gas-liquid heat exchanger 17, the degree of supercooling increases.

In this way, the heat quantity obtained from the air in the bank C1 is increased by the heat exchange in the in-bank heat exchanger 5, and therefore, the cooling capacity in the bank C1 is improved.

Further, since the evaporation of the liquid refrigerant in the interior heat exchanger 5 can be further promoted, the occurrence of the liquid impact phenomenon of the compressor 1 can be prevented.

On the other hand, during the temperature increasing operation, the liquid refrigerant flows through the piping line L7 instead of the piping line L6, and therefore the liquid-liquid heat exchanger 17 does not function.

(modification 2)

Variation 2 includes two or more internal heat exchangers (refrigeration apparatus 51B) with respect to refrigeration apparatus 51. Here, an example including two in- tank heat exchangers 25A and 25B will be described with reference to fig. 13. Fig. 13 is a partial circuit diagram mainly showing a portion of the refrigerant circuit of the refrigeration apparatus 51B different from the refrigerant circuit of the refrigeration apparatus 51 (see fig. 1).

As shown in fig. 13, the refrigeration apparatus 51B connects the interior heat exchanger 25A including the fan FM25A and the interior heat exchanger 25B including the fan FM25B in parallel between the liquid receiver 4 and the branching unit D3.

An expansion valve 22A is connected to the upstream side (the liquid receiver 4 side) of the in-bank heat exchanger 25A, and an expansion valve 22B is connected to the upstream side of the in-bank heat exchanger 25B.

The expansion valves 22A and 22B are joined at their upstream sides into a single line and connected to the liquid receiver 4 via an electromagnetic valve 23.

An electromagnetic valve 21A is provided between the in-reservoir heat exchanger 25A and the expansion valve 22A, and between the liquid receiver 4.

An electromagnetic valve 21B is provided between the in-reservoir heat exchanger 25B and the expansion valve 22B, and between the liquid receiver 4.

The downstream sides of the expansion valves 22A, 22B are combined into one line and connected to the branch portion D3.

The operations of the fans FM25A and FM25B, and the solenoid valves 21A and 21B are controlled by the controller 31.

The refrigeration apparatus 51B is mounted on a refrigeration vehicle having two or more compartments to be maintained at a constant temperature, for example.

The in-house heat exchanger 25A and the in-house heat exchanger 25B are provided to cool and heat the interiors of the different houses.

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

According to this modification 2, the cooling and heating of the two or more banks can be independently performed by combining the open state and the closed state of the respective solenoid valves 21A, 21B, and 23. For example, only a specific bank or two or more banks may be cooled, or all banks may be cooled.

Modification 1 and modification 2 can be combined as appropriate.

The flow direction regulating portion RK is not limited to being configured by using two or more check valves, but the flow direction regulating portion RK can be configured at a low cost by using a check valve.

(modification 3)

In modification 3, the refrigeration apparatus 51 is a refrigeration apparatus 57, and the refrigeration apparatus 57 has a refrigerant circuit that does not include the flow direction regulation portion RK and is capable of performing a cooling operation and a temperature increasing operation.

The structure of the refrigerating device 57 is shown in the refrigerant circuit diagram, that is, fig. 14, and fig. 15 showing the control system.

That is, the refrigerant circuit of the refrigeration apparatus 57 is configured such that the flow direction regulation portion RK is omitted from the refrigerant circuit of the refrigeration apparatus 51, and the parallel circuit LP2 is configured as a parallel circuit LP72 in which the solenoid valve 11 and the solenoid valve 13 are replaced with the check valve 71 and the check valve 73, respectively. The other structures are the same.

Since this structure does not include the flow direction regulating portion RK, the direction of the refrigerant flowing through the interior heat exchanger 5 is opposite between the cooling operation and the temperature increasing operation.

That is, in the parallel circuit LP72, when the refrigerant flows from the liquid receiver 4 into the interior heat exchanger 5, the refrigerant flows through the piping line L76; when the refrigerant flows from the interior heat exchanger 5 to the liquid receiver 4, the refrigerant flows through the piping line L77.

The cooling operation and the temperature increasing operation of the refrigerating apparatus 57 will be described mainly with reference to fig. 16 to 18.

Fig. 16 is a diagram for explaining a refrigerant circuit in the cooling operation. Fig. 17 is a diagram for explaining a refrigerant circuit in the temperature raising operation. Fig. 18 is a table for explaining the control of the control unit 31 in each operation. In fig. 17 and 18, as in fig. 9 and 10, the piping portion where the refrigerant flows is shown by a thick line, and the flow direction of the refrigerant along the piping is shown by an arrow.

(Cooling operation)

As shown in the table of fig. 18, during the cooling operation of the refrigeration apparatus 57, the control unit 31 sets the four-way valve 2 to the mode a and sets the fans FM1 and FM2 to the operating state.

The blowing directions of the fan FM1 and the fan FM2 during the cooling operation are respectively shown by arrow DR71 and arrow DR72 in fig. 16.

The phase of the refrigerant from the port 3Ba to the port 3Aa of the exterior heat exchanger 3 and the operation of the exterior heat exchanger 3 are the same as those of the cooling operation of the refrigeration apparatus 51.

That is, during the cooling operation of the refrigeration device 57, the 2 nd external heat exchanger 3B and the 1 st external heat exchanger 3A of the external heat exchangers 3 function as condensers integrally.

The gaseous refrigerant radiates heat to the outside air and condenses, and flows as a high-pressure liquid refrigerant from the port 3Aa into the pipe line L5.

The refrigerant flowing into the piping line L5 is substantially entirely in a liquid phase at a high pressure.

The liquid refrigerant flows through the liquid receiver 4 and flows into the parallel circuit LP 72.

In the parallel circuit LP72, only the liquid refrigerant is allowed to flow into the piping line L76 by the check valve 71 and enter the expansion valve 72.

In the expansion valve 72, the liquid refrigerant expands. As a result, the liquid refrigerant is reduced in pressure and temperature, and vaporization is promoted, so that the liquid refrigerant becomes a gas-liquid mixed refrigerant in which a gas phase and a liquid phase are mixed.

The gas-liquid mixed refrigerant flowing out of the expansion valve 72 flows into the interior heat exchanger 5.

In the indoor heat exchanger 5, the fan FM2 is in operation under the control of the controller 31, and the air in the cabin C1 flows in the direction of arrow DR72 in fig. 16.

In this state, the gas-liquid mixed refrigerant exchanges heat with the air in the bank C1, obtains heat from the air in the bank C1, and is completely gasified to become a gaseous refrigerant. That is, the interior heat exchanger 5 functions as an evaporator, and the interior of the bank C1 is cooled.

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

In the refrigeration apparatus 57, the piping line L8 connects the interior heat exchanger 5 and the port 2d of the four-way valve 2 without branching. Therefore, the gaseous refrigerant flows from the port 2d of the four-way valve 2 in the mode a, through the port 2c, further through the accumulator 6, and returns to the suction port of the compressor 1.

(operation at elevated temperature)

As shown in the table of fig. 18, during the temperature increasing operation of refrigerator 57, controller 31 sets four-way valve 2 to mode B, and sets fans FM1 and FM2 to an operating state.

The blowing direction of the fan FM1 and the fan FM2 during the temperature raising operation is the same as the cooling operation, and is a constant direction, which is shown by arrow DR73 and arrow DR74 in fig. 17.

As shown in fig. 17, 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 B, through the port 2d, and into the pipe line L8 under the control of the controller 31.

In the refrigeration apparatus 57, as described above, the piping line L8 connects the port 2d of the four-way valve 2 and the interior heat exchanger 5 without branching.

Therefore, the direction in which the gaseous refrigerant flows into the interior heat exchanger 5 is opposite to the direction in which the gaseous refrigerant flows into the interior heat exchanger 5 during the cooling operation.

In the indoor heat exchanger 5, as described above, the fan FM2 is in operation under the control of the controller 31, and the air in the warehouse C1 flows in the direction of arrow DR74 in fig. 17.

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

The liquid refrigerant flowing out of the interior heat exchanger 5 flows through the piping line L77 having the check valve 73 of the parallel circuit LP72 and the liquid receiver 4, and flows into the 1 st exterior heat exchanger 3A of the exterior heat exchanger 3 from the port 3Aa through the piping line L5.

In the outdoor heat exchanger 3, the fan FM1 is in operation under the control of the controller 31, and outside air flows in the direction of arrow DR73 in fig. 17. Therefore, the 1 st outdoor heat exchanger 3A is located upstream of the 2 nd outdoor heat exchanger 3B in the flow of the outside air.

In this state, the liquid refrigerant is cooled and the temperature drops in the 1 st outdoor heat exchanger 3A. That is, the 1 st outdoor heat exchanger 3A functions as a supercooling heat exchanger for the liquid refrigerant.

The gaseous refrigerant flowing into the 1 st outdoor heat exchanger 3A together with the liquid refrigerant is also cooled by the gaseous refrigerant, and substantially all of the gaseous refrigerant becomes liquid refrigerant.

The supercooled liquid refrigerant flows out of the port 3Ab of the 1 st outdoor heat exchanger 3A and flows into the pipe line L3.

In the pipe line L3, the liquid refrigerant enters the expansion valve 7 through the check valve 8.

In the expansion valve 7, the liquid refrigerant expands. As a result, the liquid refrigerant is reduced in pressure and temperature, and vaporization is promoted, so that the liquid refrigerant becomes a gas-liquid mixed refrigerant in which a gas phase and a liquid phase are mixed.

The gas-liquid mixed refrigerant flowing out of the expansion valve 7 flows into the 2 nd outdoor heat exchanger 3B from the port 3 Bb.

In the 2 nd outdoor heat exchanger 3B, the gas-liquid mixed refrigerant flowing from the port 3Bb receives heat from the outside air by heat exchange with the outside air, evaporates, turns into a gaseous refrigerant, and flows into the piping line L2 from the port 3 Ba. That is, the 2 nd external heat exchanger 3B functions as an evaporator.

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

Next, the defrosting operation of the refrigerating apparatus 57 will be described.

(defrosting operation of the heat exchanger 5 in the interior)

Even in the refrigerating device 57, if the cooling operation is performed for a long time, moisture contained in the air in the cabin C1 may freeze and frost, and adhere to the heat sink of the cabin heat exchanger 5. Since the frost on the fins hinders the heat exchange, the defrosting operation of the interior heat exchanger 5 is performed to remove the frost.

As shown in the table of fig. 18, this defrosting operation differs from the temperature raising operation only in stopping the fan FM1 and the fan FM 2.

(defrosting operation of outdoor Heat exchanger 3)

Even in the refrigeration device 57, if the temperature-raising operation is performed for a long time, moisture contained in the outside air may freeze and frost, and adhere to the fins 3f of the outdoor heat exchanger 3.

In the refrigeration apparatus 57, the outdoor heat exchanger 3 functions in the same manner as the refrigeration apparatus 51. Therefore, snow or frost is extremely unlikely to be accumulated on the fins 3f of the outdoor heat exchanger 3.

However, when the refrigerator car C is driven during snowfall, if the amount of snowfall is significantly large, the adjacent fins 3f on the upstream side (1 st bank-outside heat exchanger 3A side) of the bank-outside heat exchanger 3 may be clogged.

At this time, since heat exchange is inhibited and the heat exchanger cannot function as a heat exchanger, the defrosting operation of the exterior heat exchanger 3 is performed to melt snow and defrost the fins 3 f.

As shown in the table of fig. 18, this defrosting operation differs from the cooling operation only in stopping the fan FM1 and the fan FM 2.

The refrigerating apparatus 57 achieves the following effects particularly in the temperature increasing operation.

In the 2 nd outdoor heat exchanger 3B, the gas-liquid mixed refrigerant undergoes heat exchange for taking out heat from the outside air, and becomes a low-pressure gaseous refrigerant.

In the external heat exchanger 3, a plurality of fins 3f are provided so as to straddle the 1 st and 2 nd external heat exchangers 3A and 3B. Therefore, in the 1 st outdoor heat exchanger 3A, part of the heat released from the liquid refrigerant is transferred to the fins 3f and transferred to the 2 nd outdoor heat exchanger 3B, and is used as evaporation heat of phase change in the 2 nd outdoor heat exchanger 3B.

In this way, evaporation of the liquid refrigerant in the 2 nd outdoor heat exchanger 3B is promoted, and therefore, it is possible to prevent the liquid refrigerant from being sucked into the compressor 1, that is, the so-called liquid hammering phenomenon.

Even when the operating environment is driving in a cold district, for example, and snow is accumulated on the fins 3f due to snowfall, the snow adhering to the fins 3f is warmed and melted by the heat released by the heat exchange performed by the 1 st external heat exchanger in accordance with the temperature increasing operation.

Further, the portions of the plurality of fins 3f on the 2 nd external heat exchanger 3B side are warmed by the following reasons: the outside air whose temperature has been raised by the heat exchange in the 1 st outdoor heat exchanger 3A flows downstream; and, the heat applied to the fins 3f by the heat exchange in the 1 st external heat exchanger 3A is transferred to the downstream side of the fins 3 f.

In this way, since all the fins 3f are efficiently warmed, snow accumulation or frost formation on the fins 3f is extremely effectively prevented.

Therefore, the interval between the defrosting operations of the refrigerating device 57 is increased, and the operation efficiency is improved.

The 1 st outdoor heat exchanger 3A has two or more paths P1, P2, and the paths are arranged so as not to substantially overlap in the air blowing direction (front-rear direction) and to form substantially independent areas on the suction surface.

In this way, since unevenness in the surface temperature of the suction surface is suppressed, snow adhering to the fins 3f is uniformly melted.

(modification 4)

The parallel circuit LP1 (see fig. 1, 4, 9, and 10) connecting the port 3Ab of the 1 st external heat exchanger 3A and the port 3Bb of the 2 nd external heat exchanger 3B may be replaced with a parallel circuit LP1a without the check valve 8 as a modified example 4.

In fig. 19, the parallel circuit LP1a is depicted.

(other modification examples)

At least one of the outside-warehouse heat exchanger 3 and the inside-warehouse heat exchanger 5 is not limited to the above-described fin-and-tube heat exchanger. It may be, for example, a serpentine (serpentine) or parallel flow (parallel flow), which will also achieve the same effect.

The case where the external heat exchanger 3 is not a fin-and-tube heat exchanger will be described in detail.

First, two coil-type or parallel-flow type heat exchangers are prepared and arranged in parallel in the front-rear direction. Refrigerant pipes are connected to each other, and one of the heat exchangers functions as a1 st external heat exchanger 3A and the other functions as a2 nd external heat exchanger 3B. Further, the plurality of heat exchange fins are attached to the refrigerant pipes of the two heat exchangers so as to straddle each other, and the two heat exchangers are integrated.

The above-described embodiments and variations may be combined as much as possible.

For example, the liquid-gas heat exchanger 17 may be applied to the refrigeration apparatus 57 by combining modification 1 with modification 3.

At this time, in the portion of the refrigerant circuit shown in fig. 12, the solenoid valve 11 is replaced with the check valve 71, and the solenoid valve 13 is replaced with the check valve 73.

Claims (3)

1. A heat exchanger for a refrigeration apparatus of a finned tube type, which is used as an external heat exchanger of the refrigeration apparatus, the refrigeration apparatus being provided with a refrigerant circuit including an internal heat exchanger and an external heat exchanger, and being capable of selectively performing a cooling operation for cooling the interior of the refrigeration apparatus and a temperature raising operation for raising the temperature of the interior of the refrigeration apparatus, the heat exchanger being characterized by being provided with a heat exchanger for a refrigeration apparatus

A1 st heat exchanger having a1 st refrigerant piping line,

a2 nd heat exchanger having a2 nd refrigerant piping line connected in series to the 1 st refrigerant piping line and arranged in parallel with the 1 st heat exchanger,

a blower for blowing air to the 1 st heat exchanger and the 2 nd heat exchanger,

the pipe of the 1 st refrigerant pipe line and the pipe of the 2 nd refrigerant pipe line are connected to each other so as to orthogonally penetrate the heat sink,

the 1 st refrigerant piping line has a plurality of paths with a path number of Na, the 2 nd refrigerant piping line has a plurality of paths with a path number of Nb, wherein Na is an integer of 2 or more, Nb is an integer of 3 or more, and the path number Na and the path number Nb satisfy 2. ltoreq. Na.ltoreq.Nb,

when the blower blows air, the 1 st heat exchanger is arranged at the upstream side, the 2 nd heat exchanger is arranged at the downstream side,

in the cooling operation, after condensing the gaseous refrigerant in the 2 nd heat exchanger, the gaseous refrigerant not condensed by the 2 nd heat exchanger is condensed in the 1 st heat exchanger, and the velocity of the condensed refrigerant flowing through the pipe of the 1 st refrigerant pipe line is made higher than the velocity of the condensed refrigerant flowing through the pipe of the 2 nd refrigerant pipe line, thereby increasing the degree of supercooling of the refrigerant,

in the temperature raising operation, the supercooling degree is increased in the 1 st heat exchanger, and then the liquid refrigerant is evaporated in the 2 nd heat exchanger to be used as an evaporator,

the cooling operation and the heating operation are performed by the blower.

2. The heat exchanger for a refrigerating apparatus according to claim 1, wherein the 1 st refrigerant piping line is formed in a row and the 2 nd refrigerant piping line is formed in a plurality of rows in a blowing direction of the blower.

3. The heat exchanger for a refrigerating apparatus according to claim 1 or 2, wherein an expansion valve is provided between the 1 st refrigerant piping line and the 2 nd refrigerant piping line, and the expansion valve functions only in the temperature raising operation in which the refrigerant flows from the 1 st refrigerant piping line to the 2 nd refrigerant piping line.

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