WO2021019770A1

WO2021019770A1 - Refrigerator

Info

Publication number: WO2021019770A1
Application number: PCT/JP2019/030271
Authority: WO
Inventors: 松田　弘文; 雄亮田代
Original assignee: 三菱電機株式会社
Priority date: 2019-08-01
Filing date: 2019-08-01
Publication date: 2021-02-04
Also published as: JPWO2021019770A1; JP7175399B2

Abstract

A refrigerator (100) comprises a refrigerant circuit which includes a compressor (1), a condenser (2), a throttle device (3), an evaporator (4), and a double pipe (11) and in which refrigerant circulates through the compressor, condenser, throttle device, evaporator, and double pipe in this order. The compressor includes a suction port for sucking in refrigerant. The double pipe has an inner pipe (21) and an outer pipe (22) that is disposed so as to enclose the inner pipe and is connected to the suction port. A first space (S1) which connects the evaporator and suction port in the refrigerant circuit is formed inside the inner pipe. A second space (S2) which is demarcated from the first space by the inner pipe and is demarcated from the space outside the double pipe by the outer pipe is formed between the inner pipe and outer pipe. An end part (211) of the inner pipe and an end part (221) of the outer pipe which are located upstream of the refrigerant circuit are hermetically sealed with each other. An end part (212) of the inner pipe and an end part (222) of the outer pipe which are located downstream of the refrigerant circuit are disposed spaced apart from each other.

Description

refrigerator

The present invention relates to a refrigerator.

Conventionally, there is known a refrigerator equipped with a refrigerant circuit including a compressor, a condenser, a throttle device, and an evaporator, in which the compressor is arranged in the machine room together with the condenser.

Patent No. 5571606 discloses a refrigerator comprising a refrigerant circuit including a compressor, a condenser, a squeezing device, and an evaporator, the squeezing device including an electronic expansion valve and a capillary tube (hereinafter referred to as a capillary). .. The capillary is in contact with a pipe connecting the evaporator and the suction port of the compressor, and the refrigerant flowing through the capillary exchanges heat with the refrigerant sucked from the evaporator into the compressor.

Patent No. 557260

In the conventional refrigerator, since the compressor is arranged in the machine room together with the condenser, it is exposed to the atmosphere of the place where the compressor refrigerator is installed. Therefore, when the refrigerator is used in a humid area such as Southeast Asia and Hokkaido, the temperature of the refrigerant sucked into the compressor becomes lower than the dew point temperature of the atmosphere, and the suction pipe connected to the suction port of the compressor. Condensation may occur on the surface. Condensation corrodes metal members in the machine room, such as the floorboards in the machine room, and reduces the reliability of the refrigerator.

Further, in the refrigerator described in Japanese Patent No. 557260, the superheated refrigerant flowing out of the evaporator is sucked into the compressor after exchanging heat with the refrigerant flowing through the capillary. Since the refrigerant flowing through the capillary is expanded by the electronic expansion valve and expands while flowing through the capillary, the temperature of the refrigerant flowing through the capillary is lower than the temperature of the superheated refrigerant. As a result, the temperature of the refrigerant sucked into the compressor in the refrigerator becomes lower than the temperature of the superheated refrigerant flowing out of the evaporator, and the temperature of the refrigerant sucked into the compressor in the refrigerator without the electronic expansion valve and the capillary. Compared to, it will be lower. Therefore, in the refrigerator, dew condensation is likely to occur in the suction pipe connected to the suction port of the compressor as compared with the refrigerator without the electronic expansion valve and the capillary.

A main object of the present invention is to provide a refrigerator in which dew condensation is less likely to occur as compared with a conventional refrigerator.

The refrigerator according to the present invention includes a compressor, a condenser, a squeezing device, and an evaporator, and a double tube, and the refrigerant circulates through the compressor, the condenser, the squeezing device, the evaporator, and the double tube in order. It is equipped with a refrigerant circuit. The compressor includes a suction port for sucking the refrigerant. The double tube has an inner tube and an outer tube arranged so as to surround the inner tube and connected to the suction port. Inside the inner pipe, a first space is formed which connects the evaporator and the suction port in the refrigerant circuit. Between the inner pipe and the outer pipe, the first space is partitioned by the inner pipe, and the second space is formed by the outer pipe, which is partitioned from the outer space of the double pipe. The end portion located on the upstream side of the refrigerant circuit of the inner pipe and the end portion located on the upstream side of the refrigerant circuit of the outer pipe are hermetically sealed. The end portion located on the downstream side of the refrigerant circuit of the inner pipe and the end portion located on the downstream side of the refrigerant circuit of the outer pipe are arranged at a distance from each other.

According to the present invention, it is possible to provide a refrigerator in which dew condensation is less likely to occur as compared with a conventional refrigerator.

It is a figure which shows the refrigerant circuit of the refrigerator which concerns on embodiment. It is a figure which shows a part of the refrigerant circuit of the refrigerator shown in FIG. 1 and a machine room. It is a figure which shows the arrangement example of the double tube of the refrigerator shown in FIG. It is a partial end view which shows the region IV of the double tube of the refrigerator shown in FIG. It is a partial end view which shows the modification of the double tube of the refrigerator which concerns on embodiment. It is a partial end view which shows the other modification of the double pipe of the refrigerator which concerns on embodiment. It is a partial end view which shows the further modification of the double pipe of the refrigerator which concerns on embodiment. It is a partial end view which shows the further modification of the double pipe of the refrigerator which concerns on embodiment. It is a partial end view which shows the further modification of the double pipe of the refrigerator which concerns on embodiment. It is a partial end view which shows the further modification of the double pipe of the refrigerator which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings below, the same or corresponding parts are given the same reference numbers, and the explanations are not repeated.

<Construction of refrigerator>
As shown in FIG. 1, the refrigerator 100 according to the present embodiment includes a refrigerant circuit constituting a refrigeration cycle.

The refrigerant circuit includes the compressor 1, the condenser 2, the drawing device 3, and the evaporator 4, and the double pipe 11, the first pipe 12, and the second pipe arranged between the evaporator 4 and the compressor 1. 13 and is included. The refrigerant circuit is provided so that the refrigerant circulates in this order through the compressor 1, the condenser 2, the throttle device 3, the evaporator 4, the first pipe 12, the double pipe 11, and the second pipe 13.

The compressor 1 includes a suction port for sucking the refrigerant, a compression unit for compressing the refrigerant sucked from the suction port, and a discharge port for discharging the high-temperature and high-pressure vapor-phase refrigerant compressed by the compression unit.

The condenser 2 is provided so that the gas phase refrigerant discharged from the discharge port of the compressor 1 exchanges heat with the gas flowing along the second direction B (see FIGS. 2 and 3). As a result, the gas phase refrigerant is condensed into a liquid phase refrigerant. The flow of gas along the second direction B is formed around the condenser 2 by the blower 6.

The throttle device 3 has an electronic expansion valve 3A and a capillary 3B. The electronic expansion valve 3A and the capillary 3B are connected in series in the refrigerant circuit. The electronic expansion valve 3A is arranged closer to the condenser 2 than the capillary 3B. In other words, the capillary 3B is arranged closer to the evaporator 4 than the electronic expansion valve 3A. The drawing device 3 is provided so as to reduce the pressure of the liquid phase refrigerant condensed in the condenser 2. As a result, the liquid-phase refrigerant expands to become a gas-liquid two-phase refrigerant.

The evaporator 4 is provided so that the gas-liquid two-phase refrigerant decompressed in the throttle device 3 exchanges heat with air in a storage chamber (not shown) of the refrigerator 100. As a result, the gas-liquid two-phase refrigerant evaporates to become a gas-phase refrigerant. The evaporator 4 has an outlet through which the vapor phase refrigerant flows out. The outlet of the evaporator 4 is connected to the suction port of the compressor 1 via the first pipe 12, the double pipe 11, and the second pipe 13.

As shown in FIGS. 1 to 3, the double pipe 11 is arranged on the downstream side of the first pipe 12 and on the upstream side of the second pipe 13 in the refrigerant circuit. The extending direction of the double pipe 11 is, for example, along the vertical direction. The first pipe 12 is a so-called single pipe. The capillary 3B and the first pipe 12 form, for example, a heat exchange section 5. The heat exchange unit 5 is provided so that the refrigerant flowing through the first pipe 12 exchanges heat with the refrigerant flowing through the capillary 3B. The first pipe 12 is in contact with, for example, the capillary 3B. The second pipe 13 is connected to the suction port of the compressor 1. The second pipe 13 is a so-called single pipe. As shown in FIG. 3, the second pipe 13 has a bent portion 14 inside, for example, the machine room 101. The second pipe 13 has, for example, a portion extending along the vertical direction and a portion extending along the horizontal direction.

As shown in FIG. 2, the refrigerator 100 includes a machine room 101, a storage room (not shown), and a heat insulating portion 102. The machine room 101 houses, for example, a compressor 1, a condenser 2, an electronic expansion valve 3A, a double pipe 11, a second pipe 13, and a blower 6. The heat insulating portion 102 is arranged so as to surround the storage chamber cooled by the evaporator 4, and houses, for example, the evaporator 4, the capillary 3B, and the first pipe 12 inside. The heat insulating portion 102 has a portion arranged above the machine room 101.

As described above, the double pipe 11 and the second pipe 13 are arranged inside the machine room 101. The double pipe 11 is arranged only inside, for example, the machine room 101.

The double pipe 11 constitutes a part of the part of the refrigerant pipe connecting the evaporator 4 and the suction port of the compressor 1 in the refrigerant circuit, which is arranged in the machine room 101. The second pipe 13 constitutes the rest of the portion of the refrigerant pipe connecting the evaporator 4 and the suction port of the compressor 1 that is arranged in the machine room 101. The end portion of the double pipe 11 located on the upstream side of the refrigerant circuit is arranged in the boundary region adjacent to the heat insulating portion 102 in the machine room 101. The end of the double pipe 11 located on the downstream side of the refrigerant circuit is arranged on the upstream side of the refrigerant circuit in the machine room 101 with respect to the bent portion 14 of the second pipe 13.

As shown in FIG. 4, the double pipe 11 has an inner pipe 21 and an outer pipe 22 arranged so as to surround the inner pipe 21. The first end portion 211 of the inner pipe 21 located on the upstream side of the refrigerant circuit is connected to the end portion of the first pipe 12 located on the downstream side of the refrigerant circuit. The second end portion 212 of the inner pipe 21 located on the downstream side of the refrigerant circuit is arranged inside the outer pipe 22 and is open toward the downstream side of the refrigerant circuit.

The third end 221 located on the upstream side of the refrigerant circuit of the outer pipe 22 is connected to the first end 211 located on the upstream side of the refrigerant circuit of the inner pipe 21. The third end portion 221 and the first end portion 211 are joined by, for example, a brazing material, and are hermetically sealed by this. The fourth end 222 located on the downstream side of the refrigerant circuit of the outer pipe 22 is spaced apart from the second end 212 located on the downstream side of the refrigerant circuit of the inner pipe 21 in the thickness direction of the inner pipe 21. Is arranged. The fourth end 222 of the outer pipe 22 located on the downstream side of the refrigerant circuit is connected to the end of the second pipe 13 located on the upstream side of the refrigerant circuit.

That is, the inner pipe 21 is open on the upstream side and the downstream side of the refrigerant circuit. The outer pipe 22 is closed on the upstream side of the refrigerant circuit and is open on the downstream side.

Inside the inner pipe 21, a first space S1 that connects the evaporator 4 and the suction port of the compressor 1 in the refrigerant circuit is formed. Between the inner pipe 21 and the outer pipe 22, a second space S2 is formed which is partitioned from the first space S1 by the inner pipe 21 and is partitioned from the outer space of the double pipe 11 by the outer pipe 22. ing. The second space S2 is closed on the upstream side and open on the downstream side of the refrigerant circuit. The second space S2 is formed in an annular shape so as to surround the first space S1, for example.

Inside the second pipe 13, a third space S3 that connects the evaporator 4 and the suction port of the compressor 1 in the refrigerant circuit is formed. The third space S3 is connected to the first space S1 and the second space S2. The second space S2 is connected to the first space S1 via the third space S3. The inner pipe 21 and the outer pipe 22 are designed so that the flow of the gas phase refrigerant in the second space S2 can be regarded as a molecular flow.

The inner diameter and outer diameter of the inner pipe 21 are, for example, constant. The outer pipe 22 has a diameter-expanded portion in which the outer diameter increases from the upstream side to the downstream side of the refrigerant circuit. The inner diameter and outer diameter of the second pipe 13 are equal to the inner diameter and outer diameter of the outer pipe 22. The inner diameter and outer diameter of the first pipe 12 are equal to the inner diameter and outer diameter of the inner pipe 21.

The second pipe 13 and the outer pipe 22 are configured as one, for example. The first pipe 12 and the inner pipe 21 are configured as one, for example. From a different point of view, the double pipe 11, the second pipe 13, and the first pipe 12 are composed of, for example, the third pipe 31 and the fourth pipe 32. The outer diameter of the second pipe 13 is equal to, for example, the outer diameter of the outer pipe 22. The outer diameter of the first pipe 12 is equal to, for example, the outer diameter of the inner pipe 21.

The inner pipe 21 of the double pipe 11 is configured as a portion of the third pipe 31 arranged on the downstream side of the refrigerant circuit. The first pipe 12 is configured as a portion of the third pipe 31 arranged on the upstream side of the refrigerant circuit.

The outer pipe 22 of the double pipe 11 is configured as a portion of the fourth pipe 32 arranged on the upstream side of the refrigerant circuit. The second pipe 13 is configured as a portion of the fourth pipe 32 arranged on the downstream side of the refrigerant circuit.

The double pipe 11, the second pipe 13, and the first pipe 12 shown in FIG. 4 are formed, for example, as follows. First, the third pipe 31 and the fourth pipe 32 molded into the shape shown in FIG. 4 are prepared. The portion of the fourth pipe 32 arranged on the upstream side of the refrigerant circuit is reduced in diameter with respect to the portion of the fourth pipe 32 arranged on the downstream side of the refrigerant circuit. Next, the portion of the third pipe 31 arranged on the downstream side of the refrigerant circuit is inserted into the portion of the fourth pipe 32 arranged on the upstream side of the refrigerant circuit. Next, the portion of the fourth pipe 32 of the fourth pipe 32 arranged on the upstream side of the refrigerant circuit is joined to the portion of the third pipe 31 arranged on the downstream side of the refrigerant circuit. In this way, the double pipe 11, the second pipe 13, and the first pipe 12 shown in FIG. 4 are formed. The fourth pipe 32 may be prepared as a straight pipe whose diameter is not reduced. In this case, the portion of the fourth pipe 32 arranged on the upstream side of the refrigerant circuit is the portion of the third pipe 31 arranged on the downstream side of the refrigerant circuit is upstream of the fourth pipe 32 of the refrigerant circuit. After being inserted inside the portion arranged on the side, the diameter is reduced.

<Effect>
The refrigerant circuit of the refrigerator 100 includes a double pipe 11 arranged between the evaporator 4 and the suction port of the compressor 1. While the refrigerator 100 is in steady operation, the first space S1 and the second space S2 are sucked into the compressor 1, while the gas phase refrigerant is supplied to the first space S1 from the evaporator 4 side. The vapor phase refrigerant is not supplied to the second space S2 from the evaporator 4 side.

The ultimate temperature of the outer pipe 22 when the refrigerator 100 is in steady operation is the amount of heat exchange between the outer pipe 22 and the air in the machine room 101, and the amount of heat transfer from the compressor 1 to the second pipe 13. , And the amount increases or decreases according to the amount of heat exchange between the inner pipe 21 and the outer pipe 22. Of these, the factor that lowers the temperature of the outer pipe 22 and generates dew condensation water is the amount of heat exchange between the inner pipe 21 and the outer pipe 22. The amount of heat exchange between the inner pipe 21 and the outer pipe 22 is estimated as follows.

First, it is considered that the heat exchange between the inner pipe 21 and the outer pipe 22 during the steady operation is performed by the natural convection of the gas phase refrigerant in the second space S2. Under this assumption, the amount of heat (unit: W / m ² ) transferred from the outer pipe 22 to the inner pipe 21 is expressed by the following equation (1). In formula (1), A is the heat exchange area (unit: m ² ), T1 is the outer tube temperature (unit: K), T2 is the inner tube temperature (unit: K), and δ is the outer diameter and inner diameter of the outer tube 22. This is the difference (unit: m) from the outer diameter of the pipe 21. Wherein (1), k _e is the heat transfer coefficient of the gas-phase refrigerant that natural convection (Unit: W / (m · K) ) is expressed by the following equation (2). In formula (2), k is the thermal conductivity of the vapor-phase refrigerant (unit: W / (m · K)), L is the length of the double tube 11 in the extending direction (unit: m), and Gr is the Grashof number. , Pr is the Prandtl number. In equation (2), C, n, and m are proportional constants determined by the fluid state and the pipe shape, and are calculated experimentally.

First, the heat transfer coefficient ke was calculated by substituting the following values for each variable in the above equation (2). The Prandtl number Pr was 0.7, which is an experimental value when the extending direction of the double pipe 11 is the horizontal direction. The thermal conductivity k was 0.017 W / (m · K), which is the thermal conductivity of isobutane in a superheated state sucked into the compressor 1 during the steady operation.

Further, the heat transfer coefficient ke calculated from the above equation (2) and the following values derived assuming the above steady operation are substituted into each variable of the above equation (1) from the outer pipe 22. The amount of heat Q transferred to the inner pipe 21 was calculated. The outer tube temperature T1 was 40 ° C. (313.15K), and the inner tube temperature T2 was 25 ° C. (298.15K). The outer diameter of the outer tube 22 was 8.00 mm, the outer diameter of the inner tube 21 was 6.35 mm, and δ was 1.65 mm.

Further, the ultimate temperature of the inner pipe 21 was calculated from the calorific value Q calculated from the above formula (1). As a result of the calculation, the ultimate temperature of the inner tube 21 was 30 ° C., and the ultimate temperature of the outer tube 22 was 35 ° C. That is, when the isobutane gas naturally convects in the second space S2 as described above, the temperature decrease of the outer tube 22 is 5 ° C. or less.

Therefore, according to the refrigerator 100, it is used under operating conditions such that the temperature of the refrigerant flowing through the inner pipe 21 is 25 ° C. in an environment where the dew point temperature is about 25 ° C. (for example, the temperature is 32 ° C. and the humidity is 70%). Even in this case, since the temperature reached by the outer pipe 22 is higher than the temperature of the refrigerant flowing through the inner pipe 21 and higher than the dew point temperature, dew condensation is unlikely to occur around the outer pipe 22 of the double pipe 11.

Further, as described above, during the steady operation, the vapor phase refrigerant is supplied to the first space S1 from the evaporator 4 side, while the vapor phase refrigerant is not supplied to the second space S2 from the evaporator 4 side. Therefore, the pressure in the second space S2 is lower than the pressure in the first space S1. Pressure in the second space S2 is, for example, 10 ⁰ Pa or less. Since the thermal conductivity of the gas phase refrigerant depends on the pressure, the thermal conductivity of the gas phase refrigerant in the second space S2 is lower than the thermal conductivity of the gas phase refrigerant in the first space S1. That is, the thermal conductivity of the gas phase refrigerant in the second space S2 is lower than the thermal conductivity k of the vapor phase refrigerant in the overheated state sucked into the compressor 1 during the steady operation. As a result, considering the pressure difference between the second space S2 and the first space S1, the amount of heat transferred from the outer pipe 22 to the inner pipe 21 when the refrigerator 100 is in steady operation is estimated as described above. It becomes even less than the amount of heat generated, and the temperature reached by the outer tube 22 becomes even higher than the temperature estimated as described above.

Therefore, according to the refrigerator 100, even when the temperature of the refrigerant flowing through the inner pipe 21 is equal to or lower than the dew point temperature under the installation environment during the steady operation, the temperature reached by the outer pipe 22 is made higher than the dew point temperature. Therefore, dew condensation is unlikely to occur around the outer pipe 22 of the double pipe 11.

Further, in the refrigerator 100, the throttle device 3 includes an electronic expansion valve 3A and a capillary 3B. The electronic expansion valve 3A and the capillary 3B are arranged in series with each other in the refrigerant circuit. The capillary 3B is arranged closer to the evaporator 4 than the electronic expansion valve 3A, and is in contact with the first pipe 12 arranged between the evaporator 4 and the double pipe 11. That is, the refrigerant flowing through the first pipe 12 exchanges heat with the refrigerant flowing through the capillary 3B.

The temperature of the refrigerant flowing through the capillary 3B becomes lower as the opening degree of the electronic expansion valve 3A becomes smaller. Therefore, when the opening degree of the electronic expansion valve 3A is small, the temperature of the refrigerant flowing through the capillary 3B is lower than the temperature of the refrigerant flowing out of the evaporator 4, and the temperature of the refrigerant flowing through the first pipe 12 is the temperature of the refrigerant 4 It will be lower than the temperature of the refrigerant flowing out of. As a result, the temperature of the refrigerant flowing into the inner pipe 21 of the double pipe 11 is lower than the temperature of the refrigerant flowing out of the evaporator 4.

Even in such a case, by providing the refrigerator 100 with the above-described configuration, even when the temperature of the refrigerant flowing through the inner pipe 21 becomes lower than the dew point temperature under the installation environment during the steady operation, the outer pipe 22 Since the temperature reached is higher than the temperature of the refrigerant flowing into the inner pipe 21, dew condensation is less likely to occur around the outer pipe 22 of the double pipe 11.

<Modification example>
The refrigerant circuit of the refrigerator 100 includes, but is not limited to, the electronic expansion valve 3A and the capillary 3B as the throttle device 3, and further includes the first pipe 12 in contact with the capillary 3B. The throttle device 3 may be composed of, for example, only an expansion valve. The refrigerant circuit does not have to include the first pipe 12. In such a refrigerator 100, the temperature of the refrigerant flowing into the inner pipe 21 of the double pipe 11 is higher than that of the refrigerator 100, so that dew condensation is less likely to occur around the outer pipe 22 of the double pipe 11. That is, the refrigerator 100 can suppress the occurrence of dew condensation around the outer pipe 22 of the double pipe 11 regardless of the configuration of the drawing device 3.

In the refrigerator 100, the double pipe 11 constitutes a part of the refrigerant pipe connecting the evaporator 4 and the suction port of the compressor 1 in the refrigerant circuit, which is arranged in the machine room 101. The second pipe 13 constitutes the rest of the above portion, but is not limited to this. As shown in FIG. 5, in the refrigerator 100, the double pipe 11 is arranged in the machine room 101 of the refrigerant pipes connecting the evaporator 4 and the suction port of the compressor 1 in the refrigerant circuit. It may constitute the whole of the part. That is, the end portion of the double pipe 11 located on the downstream side of the refrigerant circuit may be connected to the suction port 1H of the compressor 1. In other words, the second end 212 located on the downstream side of the refrigerant circuit of the inner pipe 21 and the fourth end 222 located on the downstream side of the refrigerant circuit of the outer pipe 22 are the suction port 1H of the compressor 1. It may be connected to. Even in this way, the first space S1 and the second space S2 are formed inside the double pipe 11, and the pressure in the second space S2 is lower than the pressure in the first space S1. Therefore, such a refrigerator 100 can exert the same effect as the above-mentioned refrigerator 100. Further, in such a refrigerator 100, since the length of the double pipe 11 is longer than that of the refrigerator 100 described above, dew condensation is less likely to occur in the machine room 101. In the above case, the double pipe 11 may have a bent portion. Such a double pipe 11 can be assembled, for example, by joining a pre-bent inner pipe 21 and an outer pipe 22.

In the refrigerator 100, the outer pipe 22 has a diameter-expanded portion in which the outer diameter increases from the upstream side to the downstream side of the refrigerant circuit, but the present invention is not limited to this. In other words, the second space S2 faces the enlarged diameter portion of the outer pipe 22 on the upstream side of the refrigerant circuit, but is not limited to this. As shown in FIG. 6, the inner pipe 21 may have a reduced diameter portion in which the outer diameter becomes smaller from the upstream side to the downstream side of the refrigerant circuit. The second space S2 may face the reduced diameter portion of the inner pipe 21 on the upstream side of the refrigerant circuit. Further, as shown in FIG. 7, the outer pipe 22 has a diameter-expanded portion in which the outer diameter increases from the upstream side to the downstream side of the refrigerant circuit, and the inner pipe 21 of the refrigerant circuit. It may have a reduced diameter portion in which the outer diameter becomes smaller from the upstream side to the downstream side. The second space S2 may face the reduced diameter portion of the inner pipe 21 and the enlarged diameter portion of the outer pipe 22 on the upstream side of the refrigerant circuit. The first space S1 and the second space S2 are also formed in the double pipe 11 as described above. Therefore, the refrigerator 100 provided with the double tube 11 shown in FIG. 6 or FIG. 7 can exert the same effect as the refrigerator 100 provided with the double tube 11 shown in FIG.

As shown in FIG. 8, the refrigerator 100 may have a reduced diameter portion in which the outer diameter of the second pipe 13 decreases from the upstream side to the downstream side of the refrigerant circuit. The outer diameter of the portion of the second pipe 13 located on the downstream side of the refrigerant circuit from the reduced diameter portion is less than the outer diameter L2 of the outer pipe 22.

In the refrigerator 100, the first end portion 211 of the inner pipe 21 and the third end portion 221 of the outer pipe 22 are joined, but the present invention is not limited to this. As shown in FIG. 9, the first end portion 211 of the inner pipe 21 and the third end portion 221 of the outer pipe 22 may be connected via a seal member 40. The inner pipe 21 and the seal member 40 are joined by, for example, a brazing material. The outer pipe 22 and the seal member 40 are joined by, for example, a brazing material. Preferably, the thermal conductivity of the material constituting the seal member 40 is lower than the thermal conductivity of the material constituting the inner tube 21 and the outer tube 22.

In the refrigerator 100, the double pipe 11 may have at least one connecting portion for connecting the outer peripheral surface of the inner pipe 21 and the inner peripheral surface of the outer pipe 22. The connecting portion is formed as, for example, a convex portion with respect to at least one of the outer peripheral surface of the inner pipe 21 and the inner peripheral surface of the outer pipe 22. As shown in FIG. 10, the inner pipe 21 has, for example, a plurality of convex portions 21p protruding from the outer peripheral surface of the inner pipe 21. The plurality of convex portions 21p are arranged so as to be spaced apart from each other along the circumferential direction of the inner pipe 21. Each convex portion 21p is in contact with the inner peripheral surface of the outer pipe 22, and constitutes the connection portion. A plurality of second spaces S2 partitioned by a plurality of convex portions 21p are formed between the inner pipe 21 and the outer pipe 22 of the double pipe 11. In this case, if the area of the contact surface between the plurality of convex portions 21p and the outer tube 22 is large, the amount of heat exchange between the inner tube 21 and the outer tube 22 increases, and the temperature reached by the outer tube 22 described above decreases. To do. On the other hand, each convex portion 21p can suppress the deformation of the inner pipe 21 due to the pressure difference generated between the first space S1 and the second space S2. Therefore, the configuration of each convex portion 21p is determined so as to suppress the deformation of the inner tube 21 while suppressing the decrease in the reaching temperature of the outer tube 22 described above. The connection portion may be configured as a separate body from the inner pipe 21 and the outer pipe 22. Preferably, the thermal conductivity of the material constituting the connection portion is lower than the thermal conductivity of the material constituting the inner tube 21 and the outer tube 22.

Although the embodiment of the present invention has been described as described above, it is also possible to modify the above-described embodiment in various ways. Moreover, the scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

1 Compressor, 2 Condenser, 3 Squeezing device, 3A Electronic expansion valve, 3B Capillary, 4 Evaporator, 5 Heat exchange part, 6 Blower, 11 Double pipe, 12 1st pipe, 13 2nd pipe, 14 Bending part , 21 inner pipe, 22 outer pipe, 31 third pipe, 32 fourth pipe, 40 seal member, 100 refrigerator, 101 machine room, 102 heat insulation part, 211 first end, 212 second end, 221 third end Part 222, 4th end.

Claims

A refrigerant circuit including a compressor, a condenser, a drawing device, and an evaporator, and a double tube, in which a refrigerant circulates in this order through the compressor, the condenser, the drawing device, the evaporator, and the double tube. With
The compressor includes a suction port for sucking the refrigerant.
The double pipe has an inner pipe and an outer pipe arranged so as to surround the inner pipe and connected to the suction port.
Inside the inner pipe, a first space connecting the evaporator and the suction port in the refrigerant circuit is formed.
Between the inner pipe and the outer pipe, a second space is formed which is partitioned from the first space by the inner pipe and is partitioned from the outer space of the double pipe by the outer pipe. Ori,
The end of the inner pipe located on the upstream side of the refrigerant circuit and the end of the outer pipe located on the upstream side of the refrigerant circuit are airtightly sealed.
A refrigerator in which an end portion of the inner pipe located on the downstream side of the refrigerant circuit and an end portion of the outer pipe located on the downstream side of the refrigerant circuit are arranged at a distance from each other.
The throttle device includes an electronic expansion valve and a capillary arranged in series with each other in the refrigerant circuit.
The capillary is arranged on the upstream side of the refrigerant circuit with respect to the electronic expansion valve.
The refrigerant circuit further includes a first pipe arranged between the evaporator and the double pipe.
The refrigerator according to claim 1, wherein the capillary and the first pipe form a heat exchange section.
Further provided with at least a machine room for accommodating the compressor and the condenser.
The refrigerator according to claim 1 or 2, wherein the double tube is arranged only inside the machine room.
The double pipe according to claim 3, wherein the double pipe constitutes the entire portion of the refrigerant pipe connecting the evaporator and the suction port in the refrigerant circuit, which is arranged in the machine chamber. refrigerator.
The refrigerant circuit includes a second pipe arranged between the double pipe and the suction port inside the machine room.
The outer pipe is connected to the second pipe, and is connected to the second pipe.
A third space is formed inside the second pipe, which is connected between the evaporator and the suction port in the refrigerant circuit and is connected to the first space and the second space. Item 3. The refrigerator according to item 3.
The double pipe constitutes a part of a part of the refrigerant pipe connecting the evaporator and the suction port in the refrigerant circuit, which is arranged in the machine chamber.
The second pipe constitutes the rest of the portion of the refrigerant pipe connecting the evaporator and the suction port in the refrigerant circuit, which is arranged in the machine chamber.
The refrigerator according to claim 5, wherein the second pipe has a bent portion inside the machine room.
The refrigerator according to any one of claims 1 to 6, wherein the outer pipe has a diameter-expanded portion in which the outer diameter increases from the upstream side to the downstream side of the refrigerant circuit.
The refrigerator according to any one of claims 1 to 7, wherein the inner pipe has a reduced diameter portion whose outer diameter decreases from the upstream side to the downstream side of the refrigerant circuit.