CN112601921B

CN112601921B - Refrigerator with a door

Info

Publication number: CN112601921B
Application number: CN201980055235.1A
Authority: CN
Inventors: 岩本智晴; 高濑仁; 松野智彦; 濑尾达也; 渋谷真琴; 青木良太
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2018-08-31
Filing date: 2019-08-16
Publication date: 2022-12-13
Anticipated expiration: 2039-08-16
Also published as: EP3799615A1; EP3799615B1; JP2020034248A; CN112601921A; KR20200026670A; EP3799615A4

Abstract

Disclosed herein is a refrigerator including a cooling cycle mechanism having improved cooling cycle efficiency by more effectively performing heat exchange between refrigerant discharged from an evaporator and refrigerant discharged from a condenser. The refrigerator includes a cooling circulation mechanism including a compressor, a condenser, and an evaporator. The refrigerator also includes a first tube configured to include a first heat exchanger and configured to guide refrigerant from the condenser to the evaporator. The refrigerator also includes a second duct including a second heat exchanger and configured to guide the refrigerant from the evaporator to the compressor. The second heat exchanger is adjacent to the first heat exchanger and configured to exchange heat with the first heat exchanger. The first heat exchanger and the second heat exchanger are arranged to direct refrigerant in the same direction.

Description

Refrigerator with a door

Technical Field

The present disclosure relates to a refrigerator.

Background

Patent JP4238731B2 discloses a cooling circulation mechanism (cooling cycle mechanism) for a conventional refrigerator. The cooling circulation mechanism operates in such a manner that: a capillary tube installed at the middle of a tube for introducing the refrigerant discharged from the condenser into the evaporator and a suction tube for introducing the refrigerant discharged from the evaporator into the compressor are connected in parallel with each other, and thus the refrigerant flowing in the capillary tube exchanges heat with the refrigerant flowing in the suction tube, thereby improving the efficiency of the cooling cycle.

However, in the refrigerator disclosed in patent JP4238731B2, in the contact portion between the capillary tube and the suction pipe, the direction in which the refrigerant flows in the capillary tube and the direction in which the refrigerant flows in the suction pipe are opposite to each other. Thus, in practice, the heat exchange efficiency is only slightly improved, and the efficiency of the cooling cycle is not significantly improved.

More specifically, the refrigerant flowing in the capillary tube has the highest temperature on the condenser side, and the temperature of the refrigerant decreases as it goes away from the condenser. The refrigerant flowing in the suction pipe has the lowest temperature on the evaporator side, and the temperature of the refrigerant increases with distance from the evaporator.

In the refrigerator disclosed in patent JP4238731B2, heat exchange is performed between the refrigerant of the capillary tube having a relatively high temperature on the condenser side and the refrigerant of the suction pipe separated from the evaporator, while heat exchange is performed between the refrigerant of the capillary tube separated from the condenser and the refrigerant of the suction pipe having a relatively low temperature on the evaporator side, so that the heat exchange efficiency is only slightly improved.

Disclosure of Invention

Technical problem

Accordingly, it is an aspect of the present disclosure to provide a refrigerator including a cooling cycle mechanism having improved cooling cycle efficiency by more efficiently performing heat exchange between refrigerant discharged from an evaporator and refrigerant discharged from a condenser.

Additional aspects of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

Technical scheme

According to an aspect of the present disclosure, a refrigerator includes: a cooling circulation mechanism configured to circulate a refrigerant into each of the devices including the compressor, the condenser, and the evaporator; a first pipe configured to guide the refrigerant discharged from the condenser to the evaporator; and a second tube configured to guide the refrigerant discharged from the evaporator to the compressor, the first tube and the second tube being arranged in parallel with each other, and the first tube and the second tube including a heat exchanger in which the refrigerant flowing in the first tube and the refrigerant flowing in the second tube perform parallel flow.

Since the refrigerants flowing in the two heat exchangers perform parallel flow, heat exchange is performed between the relatively high-temperature refrigerant at the condenser side of the first tube and the relatively low-temperature refrigerant at the evaporator side of the second tube. Therefore, heat exchange efficiency can be greatly improved, and efficiency of the cooling cycle can be improved.

The heat exchanger of the second pipe may be installed to extend from the end of the evaporator side to the compressor side.

Since heat exchange is performed between the refrigerant flowing in the first tube and the refrigerant of the lowest temperature flowing in the second tube, heat exchange efficiency can be further improved, and efficiency of a cooling cycle can be improved.

The heat exchanger of the first tube and the heat exchanger of the second tube may be arranged as follows. That is, the heat exchanger of the first tube and the heat exchanger of the second tube may be arranged in parallel with each other in a vertical direction, and the heat exchanger of the first tube and the heat exchanger of the second tube may be arranged in parallel in a horizontal direction. The vertical direction is not limited to a completely vertical direction, but includes a substantially vertical direction. The horizontal direction is not limited to a completely horizontal direction, but includes a substantially horizontal direction.

Since at least one section where the first pipe and the second pipe intersect is provided, the heat exchanger can be formed between the first pipe and the second pipe regardless of the arrangement of the devices constituting the cooling circulation mechanism. Therefore, heat exchange can be performed between the upstream side where the refrigerant flowing in the first tube has a relatively high temperature and the upstream side where the refrigerant flowing in the second tube has a relatively low temperature, thereby improving the heat exchange efficiency of the cooling cycle mechanism. The intersecting position may include a state where the first tube and the second tube intersect each other while the first tube and the second tube are in contact with each other.

The first tube may include an expander configured to expand refrigerant discharged from the condenser. In this case, the expander may be a capillary tube constituting at least a part of the first tube, and the heat exchanger of the first tube may be constituted using the capillary tube. The expander may be an expansion valve installed at a middle portion of the first pipe.

The refrigerator may further include an insulation member configured to cover at least a portion of the two heat exchangers.

Since the two heat exchangers are arranged inside the heat insulating member, heat exchange is more effectively performed between refrigerants flowing in the two heat exchangers. The outer wall of the refrigerator case may serve as the heat insulating member.

The heat insulating member may cover at least upstream sides of the two heat exchangers, and the heat insulating member may further cover portions of the first and second tubes other than the two heat exchangers.

The heat exchanger may be disposed between a machine room in which at least one of the compressor and the condenser is placed and a sub-cooling room in which the evaporator is placed. The heat exchanger of the first tube may be disposed on the machine chamber side, and the heat exchanger of the second tube may be disposed on the sub-cooling chamber side.

The heat exchanger in which the high-temperature refrigerant of the first tube flows may be disposed on a machine chamber side in which the device that becomes hot is placed, and the heat exchanger in which the low-temperature refrigerant of the second tube flows may be disposed on a sub-cooling chamber side in which the device that becomes cold is placed. Thus, the heat exchange rate in the heat exchanger can be increased.

Before the following detailed description is performed, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation; the term "or" is inclusive, meaning and/or; the phrases "and 8230; \ 8230, related to and" related to it "and their derivatives may mean including, included in, 8230; \8230, including, included in, and with, 8230, the \8230, interconnecting, including, included in, 8230, including, connected to, 8230, or with, 8230, the \8230, connecting, combining to, 8230, or with, 8230, the \8230, combining with, may be with, 8230, the \8230, communicating, with, 8230, the \8230, collaboration, interleaving, juxtaposition, proximity, binding to, the \8230, or with, the \8230, binding, having, properties of, 8230, and the like; the term "controller" means any device, system or component thereof that controls at least one operation, and such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely.

Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

Advantageous effects

As is apparent from the above description, by using the cooling cycle mechanism of the refrigerator, it may be possible to improve the efficiency of the cooling cycle by effectively exchanging heat between the refrigerant discharged from the evaporator and the refrigerant discharged from the condenser.

Drawings

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which like reference numbers represent like parts:

fig. 1 illustrates a perspective view of a refrigerator according to an embodiment of the present disclosure;

fig. 2 is a sectional view illustrating a state in which a second housing member (cooling unit) of a refrigerator according to an embodiment of the present disclosure is connected to a first housing member;

fig. 3 is a sectional view illustrating a state where a second case member (cooling unit) of the refrigerator according to an embodiment of the present disclosure is not connected to a first case member;

FIG. 4 shows a perspective view of a cooling unit according to an embodiment of the present disclosure;

FIG. 5 shows a schematic diagram of a cooling cycle according to an embodiment of the present disclosure; and

fig. 6a and 6b show schematic diagrams of heat exchangers of a first tube and a second tube according to embodiments of the present disclosure.

Detailed Description

Fig. 1 through 6b, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the disclosure may be implemented in any suitably arranged system or device.

The present disclosure will be described more fully hereinafter with reference to the accompanying drawings.

The refrigerator 100 according to the embodiment is mainly used for general households. However, the present disclosure is applicable not only to a home refrigerator but also to a commercial refrigerator. Further, the refrigerator according to the embodiment includes not only a refrigerator provided with a refrigerating compartment and a freezing compartment but also a refrigerator provided with only a refrigerating compartment or a refrigerator provided with only a freezing compartment.

< example >

As shown in fig. 1 and 2, the refrigerator 100 according to the embodiment includes a refrigerator case (BD) forming an Internal Space (IS) and a cooling Circulation Mechanism (CM) provided with each device configured to cool the internal space IS. Further, the cooling cycle mechanism CM according to the embodiment includes a compressor 20, a blower fan 21, a condenser 22, and two evaporators 23 corresponding to each device.

The refrigerator case BD is formed in such a manner: its opposite side surfaces, rear surface (rear surface), top surface and bottom surface are surrounded by the outer wall 10, and its front surface (front surface) is open. A pair of doors (D) is mounted in the refrigerator case BD by hinges to close the opening. In addition, as shown in fig. 2, the refrigerator case BD is divided into two case members (BD 1 and BD 2) along a predetermined Separation Surface (SS). Specifically, the refrigerator case BD is divided into two case members BD1 and BD2 along an inclined separation surface SS extending from a rear surface (rear surface) to a bottom surface.

Therefore, the two case elements BD1 and BD2 are all formed by the heat insulating member for forming the outer wall 10 of the refrigerator case BD. More specifically, the two case elements BD1 and BD2 are formed by a heat insulating member formed by foaming a heat insulating member such as urethane resin in a case material generally used as the outer wall 10 of the refrigerator case BD.

As shown in fig. 2 and 3, between the two housing elements BD1 and BD2, one side housing element BD1 (hereinafter referred to as "first housing element BD 1") occupies a major portion of the internal space IS and IS disposed on the front side around the separation surface SS. Further, in the first housing element BD1, a partition 11 configured to divide the internal space IS into a front side and a separation surface SS side IS installed inside the internal space IS. In the first housing element BD1, a storage chamber (SR) configured to be opened and closed by a pair of doors D is disposed at a front side of the partition 11, and a part of a sub-cooling Chamber (CR) configured to sub-cool gas cooling the storage chamber SR is formed at a separation surface SS side of the partition 11. Although not shown, the first housing element BD1 according to the embodiment is provided with a partition configured to divide the storage chamber SR and the sub-cooling chamber CR into left and right to divide the storage chamber SR and the sub-cooling chamber CR for refrigeration and freezing.

In the storage chamber SR, a plurality of shelves 12 are provided at an upper side, and a plurality of drawers (not shown) are provided at a lower side. The partition 11 is provided with an inlet 11a and an outlet 11b, the inlet 11a introducing gas from the storage chamber SR to the sub-cooling chamber CR along the bottom surface, and the outlet 11b transporting gas from the sub-cooling chamber CR to the storage chamber SR along the rear surface. The first housing element BD1 is provided with a duct 30 extending from an outlet 11b provided in the partition 11 to the storage chamber SR. The duct 30 is provided with an air inlet 30a installed according to the height of each shelf 12 or drawer, and a fan 31 is installed around the outlet 11b of the partition 11.

Between the two housing elements BD1 and BD2, the other side housing element BD2 (hereinafter referred to as "second housing element BD 2") is connected to the first housing element BD1 to form the sub-cooling chamber CR together with the first housing element BD1. Further, the second case element BD2 forms a Mechanical Room (MR) at an external space of the refrigerator, and the mechanical room MR accommodates the compressor 20, the blower fan 21, and the condenser 22. The second housing element BD2 is provided with two evaporators 23 on the inner space forming the subcooling chamber CR. Both the second case member BD2 and the cooling circulation mechanism CM are mounted on the support plate (B) together with the Control Box (CB) to constitute a cooling unit. Therefore, the second case member BD2 can be detachably attached to the first case member BD1 as a cooling unit.

When the first housing element BD1 and the second housing element BD2 are connected to each other, the storage chamber SR and the sub-cooling chamber CR are formed in the inner space, and the machine chamber MR is formed in the outer space. Among the devices constituting the cooling circulation mechanism CM, the evaporator 23 is placed in the sub-cooling chamber CR in the internal space, and the compressor 20, the blower fan 21, and the condenser 22 are placed in the machine room MR in the external space. In addition, according to the embodiment, when the first housing element BD1 and the second housing element BD2 are connected, the sub-cooling chamber CR is divided into left and right, and the evaporator 23 is positioned in one sub-cooling chamber CR for cooling and one sub-cooling chamber CR for freezing, respectively. That is, one of the two evaporators 23 serves as a refrigerating evaporator 23a, and the other serves as a freezing evaporator 23b.

Further, as shown in fig. 5, each device constituting the cooling circulation mechanism CM is connected by a plurality of pipes, and each device is configured to circulate a refrigerant in the pipes. Specifically, the device disposed on the mechanical room MR side is connected to the device disposed on the sub-cooling room CR side through a first pipe P1 that introduces the refrigerant discharged from the condenser 22 into the refrigeration evaporator 23a and a second pipe P2 that introduces the refrigerant discharged from the freezing evaporator 23b into the compressor 20. Further, the devices disposed on the machine room MR side are connected to each other through a third pipe P3 that introduces the refrigerant discharged from the compressor 20 to the condenser 22, and the devices disposed on the sub-cooling room CR side are connected to each other through a fourth pipe P4 that introduces the refrigerant discharged from the refrigeration evaporator 23a to the freezing evaporator 23b. Thus, the compressor 20, the condenser 22, and the two

evaporators

23a and 23b, which constitute the cooling circulation mechanism CM, are connected to each other through each tube, and thus a refrigerant circulates through each of these devices.

Further, the first pipe P1 is provided with an expander P1a, and the expander P1a is configured to expand the refrigerant flowing in the first pipe P1 before the refrigerant flows into the refrigeration evaporator 23a. According to the embodiment, the expander P1a corresponds to a capillary tube (indicated by a dotted line in fig. 4) forming a part of the first pipe P1. The capillary tube according to the embodiment constitutes the downstream side of the first pipe P1.

In addition, the first pipe P1 and the second pipe P2 are arranged to have a section (S) as a portion intersecting on the downstream side. The first pipe P1 and the second pipe P2 are provided with

heat exchangers

24a and 24b. The

heat exchangers

24a and 24b are positioned on the upstream side of the intersecting section, and the heat exchanger 24a and the heat exchanger 24b are arranged in parallel to exchange heat between the refrigerant flowing in the first tubes P1 and the refrigerant flowing in the second tubes P2. For example, the heat exchanger 24a of the first pipe P1 and the heat exchanger 24b of the second pipe P2 are connected in parallel with each other (see fig. 6 a). The first pipe P1 and the second pipe P2 according to the embodiment form the

heat exchangers

24a and 24b by connecting the middle portion of the capillary tube P1a constituting the first pipe P1 to the end portion of the second pipe P2 on the evaporator 23b side.

In addition, both of the

heat exchangers

24a and 24b are arranged to perform parallel flow of the refrigerant flowing in the first tubes P1 and the refrigerant flowing in the second tubes P2. That is, the refrigerant flowing in the heat exchanger 24a of the first tube P1 and the refrigerant flowing in the heat exchanger 24b of the second tube P2 flow in the same direction.

Further, as shown in fig. 4, at least a part of the

heat exchangers

24a and 24b is placed in the heat insulating member constituting the second housing element BD2. Specifically, the first pipe P1 extends from the machine room MR side to pass through the inside of the second housing element BD2, and then reaches the sub-cooling room CR side. The second pipe P2 extends from the recooling chamber CR side to pass through the inside of the second housing element BD2 and then to the machine chamber MR side. Sections of the first and second pipes P1 and P2 passing through the inside of the second housing element BD2 correspond to the

heat exchangers

24a and 24b. Therefore, both of the

heat exchangers

24a and 24b are covered with the heat insulating member constituting the second casing element BD2.

As shown in fig. 4, both of the

heat exchangers

24a and 24b pass through a section (heat insulating member) of the second housing element BD2 that is divided between the mechanical chamber MR and the evaporator 23a in the sub-cooling chamber CR. Both

heat exchangers

24a and 24b extend in a serpentine manner in the second housing element BD2. Accordingly, the distance in the longitudinal direction between the heat exchangers 24a of the first tubes P1 and the heat exchangers 24b of the second tubes P2 can be ensured, and thus a sufficient distance can be ensured for heat exchange. The upstream end of the first pipe P1 constituting the heat exchanger 24a extends toward the machine chamber MR and is connected to the condenser 22, and the downstream end thereof extends toward the sub-cooling chamber CR and is connected to the refrigeration evaporator 23a. The upstream end of the second pipe P2 constituting the heat exchanger 24b extends toward the sub-cooling chamber CR and is connected to the freezing evaporator 23b, and the downstream end thereof extends toward the machine chamber MR and is connected to the compressor 20.

Therefore, the first pipe P1 is configured to cool the high-temperature and high-pressure liquid refrigerant discharged from the condenser 22 to some extent by using the heat exchanger 24a, and to flow the liquid refrigerant and the gas refrigerant in a two-phase state to the refrigeration evaporator 23a. The second pipe P2 is configured to heat the gas refrigerant of low temperature and low pressure discharged from the freezing evaporator 23b to some extent by using the heat exchanger 24b, and is configured to flow the refrigerant to the compressor 20. Accordingly, heat generated from the first and second pipes P1 and P2 can be effectively utilized, thereby improving the efficiency of the cooling cycle.

In addition, as shown in fig. 6a, the heat exchanger 24a of the first pipe P1 is arranged on the machine room MR side, and the heat exchanger 24b of the second pipe P2 is arranged on the sub-cooling room CR side. In other words, the heat exchanger 24a of the first pipe P1 and the heat exchanger 24b of the second pipe P2 are arranged with respect to each other in the vertical direction. As shown in fig. 6b, the heat exchanger 24a of the first pipe P1 and the heat exchanger 24b of the second pipe P2 may be arranged with respect to each other in a horizontal direction.

< other examples >

In the above embodiment, a capillary tube is used as the expander P1a of the first pipe P1, but the present disclosure is not limited thereto. Therefore, the expansion valve can be used as the expander P1a. In this case, although either or both of the upstream side and the downstream side of the expansion valve of the first pipe P1 are used as the heat exchanger 24a, the same heat exchange efficiency can be obtained.

In the above embodiment, the

heat exchangers

24a and 24b are formed in the middle between the first pipe P1 and the second pipe P2. However, the heat exchanger 24b of the second pipe P2 is formed at the end portion on the evaporator 23 side. In this case, the coldest refrigerant discharged from the evaporator 23 to the second tubes P2 may be used to exchange heat with the refrigerant flowing in the first tubes P1, thereby further improving heat exchange efficiency.

However, when the above-described configuration is adopted, it is required that the first pipe P1 extends from the machine chamber MR to pass through the second housing element BD2 and bypass the sub-cooling chamber CR, and then passes through the inside of the second housing element BD2 together with the second pipe P2.

In the above embodiment, the first pipe P1 and the second pipe P2 are arranged to have the section S as a portion intersecting on the downstream side. However, the section S where the first pipe P1 and the second pipe P2 intersect is not limited to the downstream side, and thus the section S may be arranged on the upstream side or the center. That is, according to the arrangement of the devices constituting the cooling circulation mechanism CM (specifically, the arrangement of the compressor 20 and the condenser 22 in the outer space and the arrangement of the evaporator 23 in the inner space), the intersecting section S may be arranged at the middle between the first pipe P1 and the second pipe P2. Alternatively, the heat exchanger 24 may be formed without the section S where the first pipe P1 and the second pipe P2 intersect, depending on the arrangement of the devices constituting the cooling circulation mechanism CM.

In the above embodiment, the heat exchanger 24 is formed at one position in the middle between the first and second tubes P1 and P2, but the heat exchanger 24 may be intermittently formed at a plurality of positions.

In the above embodiment, a configuration is adopted in which only the

heat exchangers

24a and 24b of the first and second tubes P1 and P2 pass through the inside of the second case member BD2, but is not limited thereto. Therefore, a configuration may be adopted in which, in addition to the

heat exchangers

24a and 24b of the first and second pipes P1 and P2, other portions may pass through the inside of the second case member BD2.

In the above embodiment, the refrigerator is described as a type in which the cooling circulation mechanism CM is detachable from the cooling unit. However, the present disclosure may be applied to a refrigerator in which the cooling circulation mechanism CM is not detachable.

While the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to embrace such alterations and modifications as fall within the scope of the appended claims.

Claims

1. A refrigerator, comprising:

a cooling circulation mechanism including a compressor, a condenser, a refrigerating evaporator, and a freezing evaporator connected to the refrigerating evaporator, and configured to cool an inner space of the refrigerator;

a first tube including a first heat exchanger and configured to guide refrigerant from the condenser to the refrigeration evaporator; and

a second tube including a second heat exchanger and configured to guide the refrigerant from the freezing evaporator to the compressor,

wherein the second heat exchanger is adjacent to the first heat exchanger and is configured to exchange heat with the first heat exchanger,

wherein the first heat exchanger and the second heat exchanger are arranged to direct refrigerant in the same direction,

wherein the first heat exchanger and the second heat exchanger are bent in a serpentine manner and are in contact with each other,

wherein the first heat exchanger and the second heat exchanger are arranged in parallel with each other,

the refrigerator further includes:

a machine chamber in which the compressor and the condenser are accommodated;

a sub-cooling chamber in which the evaporator is housed; and

a second housing element configured to separate the machine chamber from the sub-cooling chamber and comprising an insulating member,

wherein a portion of the first heat exchanger and the second heat exchanger bent in a serpentine manner is located in the insulation member.

2. The refrigerator of claim 1, wherein:

the first heat exchanger is disposed at a portion of the first tube closer to the condenser, and

the second heat exchanger is disposed at a portion of the second tube closer to the evaporator.

3. The refrigerator of claim 1, wherein:

at least a portion of the second tube intersects the first tube.

4. The refrigerator of claim 1, wherein:

the second tube is parallel to the first tube.

5. The refrigerator of claim 1, wherein the insulation member is configured to:

surrounds a portion of the first heat exchanger closer to the condenser, and

surrounding a portion of the second heat exchanger that is closer to the evaporator.

6. The refrigerator of claim 1, wherein:

the first heat exchanger is disposed closer to the machine chamber than the sub-cooling chamber, and

the second heat exchanger is disposed closer to the sub-cooling chamber than the mechanical chamber.

7. The refrigerator of claim 1, wherein:

the first tube includes an expander configured to expand refrigerant.

8. The refrigerator of claim 7, wherein:

the expander is arranged to form at least part of the first heat exchanger.

9. The refrigerator of claim 8, wherein:

the expander comprises a capillary tube or an expansion valve.

10. The refrigerator of claim 1, further comprising:

a first housing element in which a storage compartment is provided;

wherein the cooling circulation mechanism is provided in the second housing member, the second housing member being detachably joined to the first housing member.

11. The refrigerator of claim 10, wherein:

the second housing element forms a sub-cooling chamber with the first housing element when the second housing element is joined to the first housing element, and

the second heat exchanger is disposed closer to the sub-cooling chamber than the first heat exchanger.

12. The refrigerator of claim 1, wherein:

the first heat exchanger is positioned upstream with respect to a flow direction of the refrigerant passing through the first tube, and

the second heat exchanger is positioned upstream with respect to a flow direction of the refrigerant through the second tube.