JP2010007985A - Cooling apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably perform heat exchange for a refrigerant in a heat exchange part even if a cooling load changes. <P>SOLUTION: This cooling apparatus includes a secondary circuit 44, which connects a secondary heat exchange part 46 adapted to condense a gas phase secondary refrigerant to make a liquid phase secondary refrigerant, and an evaporator EP adapted to vaporize the liquid phase secondary refrigerant to make a gas phase secondary refrigerant to each other using a liquid pipe 48 and a gas pipe 50, and which circulates the liquid phase secondary refrigerant from the secondary heat exchange part 46 to the evaporator EP through the liquid pipe 48, and circulates the gas phase refrigerant from the evaporator EP to the secondary heat exchange part 46 through the gas pipe 50. In the secondary circuit 44, a gas pipe 50 connecting the evaporator EP and the secondary heat exchange part 46 includes a preliminary heat exchange part 54, which causes the gas phase secondary refrigerant circulating through the pipe to come into contact with a heat exchanger HE to be cooled before flowing into the secondary heat exchange part 46. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cooling device including a refrigerant circuit in which a refrigerant circulates naturally.

  There is a cooling device that includes a primary circuit that mechanically circulates the primary refrigerant and a secondary circuit that naturally circulates the secondary refrigerant, and is configured to exchange heat between the primary refrigerant and the secondary refrigerant (for example, patents). Reference 1). As shown in FIG. 8, the primary circuit 92 of the cooling device 90 includes a compressor CM that compresses the gas phase primary refrigerant, a condenser CD that liquefies the compressed primary refrigerant, and an expansion that reduces the pressure of the liquid phase primary refrigerant. The valve EV and a primary heat exchange unit 96 that is provided in the heat exchanger 94 and vaporizes the liquid phase primary refrigerant are connected by a pipe 98. In addition, the secondary circuit 100 is provided in a heat exchanger 94 to connect a secondary heat exchange unit 102 for liquefying the gas phase secondary refrigerant and an evaporator EP for vaporizing the liquid phase secondary refrigerant into separate pipes 104 and 106. Connected and configured. The cooling device 90 is configured so that the evaporator EP is finally cooled by heat exchange between the primary refrigerant and the secondary refrigerant in the heat exchanger 94. In the refrigeration equipment provided with the cooling device 90, the constituent members CM, CD, EV and the heat exchanger 94 of the primary circuit 92 are disposed in an open space exposed to the outside air and are opened via the base plate 110. An evaporator EP constituting the secondary circuit 100 is disposed in a closed space defined below the space so as to cool the closed space. Reference numeral 108 denotes an expansion tank provided to buffer the increase in internal pressure of the secondary circuit 100.

In the cooling device 90, the secondary refrigerant is naturally circulated in the secondary circuit 100 by liquefying the gas phase secondary refrigerant in the heat exchanger 94 cooled by the primary refrigerant mechanically forcedly circulated in the primary circuit 92. It is configured to In the heat exchanger 94, the liquid phase secondary refrigerant circulates in an annular shape over the entire inner surface of the secondary heat exchange unit 102, and the gas phase secondary refrigerant circulates in the center of the secondary heat exchange unit 102. It has been found that the heat transfer area can be secured most widely in the state where the flow is generated, and the heat transfer characteristic with the primary refrigerant flowing through the primary heat exchange unit 96 is high.
JP 2002-48484 A

  By the way, in the secondary circuit 100, when the dryness and superheat degree of the gas phase secondary refrigerant flowing into the secondary heat exchange unit 102 are in a high state, the secondary refrigerant flows in the annular heat flow in the secondary heat exchange unit 102. , The heat transfer area of the secondary refrigerant is reduced, and the efficiency of heat exchange with the primary refrigerant is reduced. In addition, the cooling device 90 is constantly changing its cooling capacity required by changes in ambient temperature, defrosting of the evaporator EP, opening / closing of the door that closes the closed space, rotational speed control of the inverter type compressor CM, etc. The heat transfer area that is not effectively used in the secondary heat exchange unit 102 also changes due to such a change in the operating state. That is, if the cooling load of the evaporator EP is low and the degree of superheat of the secondary refrigerant flowing into the secondary heat exchange unit 102 is small, the sensible heat to be removed is small, so that the secondary heat exchange unit 102 is in a relatively early stage. The liquid phase secondary refrigerant appears and forms an annular flow quickly, so there is little loss of heat transfer area. On the other hand, if the cooling load of the evaporator EP is large and the degree of superheat of the secondary refrigerant flowing into the secondary heat exchange unit 102 is large, the sensible heat to be removed is large, so that the secondary heat exchange unit 102 uses the liquid phase secondary refrigerant. Is difficult to appear, and a large heat transfer area is required until an annular flow is formed, resulting in a large loss of heat transfer area.

  If the cooling device 90 is designed to be suitable when the cooling load is small, the heat exchange performance in the heat exchanger 94 may be insufficient when the cooling load increases, and cooling failure may occur due to a decrease in refrigerant circulation efficiency. is there. However, if the cooling device 90 is designed to be suitable when the cooling load is large, the heat exchanger 94 increases in weight, volume, and cost due to enlargement, and the internal volume of the heat exchanger 94 also increases. Since both the primary refrigerant and the secondary refrigerant are used in an increased amount and the paths of the primary circuit and the secondary circuit are lengthened, there is a problem that the pressure loss is increased and the refrigerant circulation efficiency is lowered. Thus, it is difficult to optimally design the heat exchanger 94 with respect to the changing cooling load, and the heat exchanger 94 has a compromise configuration that matches intermediate characteristics between when the cooling load is large and when the cooling load is small. That is, it is difficult to improve the heat exchange efficiency between the primary refrigerant and the secondary refrigerant in the heat exchanger 94 only by changing the internal volume and shape of the heat exchanger 94.

  That is, the present invention has been proposed in view of the above-described problems inherent in the cooling device according to the prior art, and has been proposed to suitably solve these problems. An object of the present invention is to provide a cooling device capable of stably performing the above.

In order to overcome the above-mentioned problems and achieve the intended object, the cooling device of the invention according to claim 1 of the present application includes:
A heat exchange unit that condenses the gas-phase refrigerant to form a liquid-phase refrigerant and an evaporator that vaporizes the liquid-phase refrigerant to form a gas-phase refrigerant are connected by a liquid pipe and a gas pipe. In the cooling device in which the refrigerant circuit configured to distribute the refrigerant from the heat exchanger to the evaporator and to distribute the gas-phase refrigerant from the evaporator to the heat exchanger via the gas pipe is provided.
The gas pipe connecting the evaporator and the heat exchanging part is provided with a preliminary heat exchanging part that cools the gas phase refrigerant flowing through the gas pipe before flowing into the heat exchanging part.
According to the first aspect of the invention, prior to liquefying the gas phase refrigerant in the heat exchange unit, the gas phase refrigerant is cooled in the preliminary heat exchange unit to reduce the degree of superheat and dryness. It is possible to quickly form an annular flow of the refrigerant in the exchange part and suppress the loss of the heat transfer area. That is, even if the cooling load fluctuates, heat exchange can be performed efficiently at the heat exchange section.

In the invention according to claim 2, a primary circuit that mechanically forcibly circulates the primary refrigerant by the compressor;
The refrigerant circuit as a secondary circuit for naturally circulating the secondary refrigerant;
A heat exchanger that is provided with a primary heat exchange part of the primary circuit and a heat exchange part of the refrigerant circuit, and exchanges heat between the primary refrigerant that circulates through the primary heat exchange part and the secondary refrigerant that circulates through the heat exchange part; With
The preliminary heat exchanging section is arranged to be in contact with the outer surface of the heat exchanger.
According to the invention which concerns on Claim 2, the cooling capability which may be lost as a heat dissipation loss can be effectively utilized by using a heat exchanger as a cooling means of a preliminary heat exchange part.

According to a third aspect of the present invention, the heat exchanger has the primary heat connected to the outside of the heat exchanging portion having a lower end connected to the liquid pipe and an upper end connected to the gas pipe with a primary refrigerant circulation space. The gist is that the heat exchanger is covered with an exchange part, and the primary heat exchange part is an outer shell of the heat exchanger.
According to the invention which concerns on Claim 3, the cooling capability which may be lost as a heat dissipation loss can be effectively utilized by using a primary heat exchange part as a cooling means of a preliminary | backup heat exchange part.

In the invention according to claim 4, a primary circuit mechanically forcibly circulating the primary refrigerant by the compressor,
The refrigerant circuit as a secondary circuit for naturally circulating the secondary refrigerant;
A heat exchanger that is provided with a primary heat exchange part of the primary circuit and a heat exchange part of the refrigerant circuit, and exchanges heat between the primary refrigerant that circulates through the primary heat exchange part and the secondary refrigerant that circulates through the heat exchange part; With
The summary is that the preliminary heat exchange section is configured to exchange heat with a low-pressure side pipe of the primary circuit from the decompression means in the primary circuit to the compressor through the primary heat exchange section.
According to the invention of claim 4, by using the low-pressure side pipe of the primary circuit having a relatively low temperature as the cooling means of the preliminary heat exchange section, the cooling capacity that may be lost as a heat dissipation loss is effectively used. Can do.

The invention according to claim 5 is characterized in that the preliminary heat exchanging section is configured such that the circulation path of the secondary refrigerant extends longer than the shortest path connecting the inflow end and the outflow end of the preliminary heat exchange section. And
According to the invention which concerns on Claim 5, the internal volume of a refrigerant circuit can be increased only by the content integral of a preliminary | backup heat exchange part, and the pressure rise of a refrigerant circuit can be buffered with this internal volume.

The gist of the invention according to claim 6 is that the preliminary heat exchange section is provided in a machine room in which the heat exchange section is installed.
According to the invention of claim 6, by arranging the preliminary heat exchange part in the machine room in which the heat exchange part is installed, it is easy to connect the heat exchange part and the gas pipe, and the maintainability is improved. Can do.

The gist of the invention according to claim 7 is that the preliminary heat exchange section is configured to exchange heat with the liquid pipe.
According to the invention which concerns on Claim 7, the cooling capacity which may be lost as a heat dissipation loss can be effectively utilized by using liquid piping as a cooling means of a preliminary heat exchange part.

  The cooling device according to the present invention can stably perform heat exchange of the secondary refrigerant in the heat exchange section even when the cooling load varies.

  Next, the cooling device according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments. In addition, an Example demonstrates and demonstrates the cooling device provided in the large sized refrigerator which can be used for business uses, such as a store, and can accommodate articles, such as vegetables and meat, in large quantities. The same members and structures as those described in the prior art are denoted by the same reference numerals.

  As shown in FIG. 1, a refrigerator 10 according to an embodiment includes a box 12 having a heat insulating structure that internally defines a storage room (closed space) 14, and is provided above the box 12. And a cabinet 16 configured as described above. In the box 12, an opening portion 12 a that opens to the front side and serves as an entry / exit port for goods is opened in communication with the storage chamber 14. Further, a heat insulating door 22 is rotatably disposed at a front portion of the box body 12 by a hinge (not shown), and by opening the heat insulating door 22, an article can be taken into and out of the storage chamber 14 through the opening 12a. In addition, the storage chamber 14 can be sealed by closing the heat insulating door 22.

  Inside the cabinet 16 is a machine room (open space) 20 in which a part of a cooling device 32 for cooling the storage chamber 14 and a control electrical box C for controlling the cooling device 32 are arranged. (See FIG. 2). At the bottom of the machine room 20, a base plate 24 that is placed on the top plate 12 b of the box 12 and serves as a common substrate for the devices disposed in the machine room 20 is installed. The metal panel 18 forming the outer wall of the cabinet 16 is provided with air circulation holes (not shown) communicating with the machine room 20 at appropriate locations, and the atmosphere in the machine room 20 and the outside air are communicated through the air circulation holes. And are to be replaced. In addition, the cabinet 16 is not provided with the metal panel 18 which becomes the ceiling of the refrigerator 10, and the upper part of the machine room 20 is opened.

  In the upper part of the storage chamber 14, a cooling duct 26 is disposed at a predetermined distance from the lower surface of the top plate 12b in the box 12, and the cooling duct 26 and a notch formed in the top plate 12b of the box 12 are provided. A cooling chamber 28 is defined between the base plate 24 facing the storage chamber 14 via 12c. The cooling chamber 28 communicates with the storage chamber 14 through a suction port 26a formed on the front side of the bottom of the cooling duct 26 and a cold air outlet 26b formed on the rear side, and a part of the storage chamber 14 as a closed space is formed. It is composed. A blower fan 30 is disposed at the suction port 26a. By driving the blower fan 30, the air in the storage chamber 14 is taken into the cooling chamber 28 from the suction port 26a, and the cool air in the cooling chamber 28 is drawn from the cool air outlet 26b. It is sent to the storage chamber 14. The notch 12c of the top plate 12b is hermetically closed by the base plate 24, and the storage chamber 14 (cooling chamber 28) and the machine room 20 are separated from each other by the base plate 24 and become independent spaces. (See FIG. 1).

  As shown in FIG. 4, the cooling device 32 includes two circuits, a mechanical compression primary circuit 34 that forcibly circulates a refrigerant, and a secondary circuit (refrigerant circuit) 44 that includes a thermosiphon that naturally convects the refrigerant. A secondary loop refrigeration circuit connected so as to exchange heat via the heat exchanger HE (cascade connection) is employed. The heat exchanger HE is formed in a separate system from the primary heat exchange unit 36 constituting the primary circuit 34 and the primary heat exchange unit 36, and the secondary heat exchange unit (heat exchange unit) constituting the secondary circuit 44. 46, and the heat exchanger HE is disposed directly above the compressor CM (see FIG. 2). That is, an independent refrigerant circulation path is formed in each of the primary circuit 34 and the secondary circuit 44, and the secondary refrigerant circulating in the secondary circuit 44 has no toxicity, flammability, and corrosive safety. High carbon dioxide is adopted. On the other hand, as the primary refrigerant circulating in the primary circuit 34, an HC refrigerant such as butane or propane having excellent characteristics as a refrigerant such as heat of evaporation or saturation pressure, ammonia, or the like is adopted. In the embodiment, isobutane is used. Or propane is used.

  The primary circuit 34 includes a compressor CM for compressing the gas phase primary refrigerant, a condenser CD for liquefying the compressed primary refrigerant, an expansion valve EV as a pressure reducing means for reducing the pressure of the liquid primary refrigerant, and a liquid phase. The heat exchanger HE that vaporizes the primary refrigerant is connected to the primary heat exchange unit 36 by a refrigerant pipe 38 (see FIG. 4). Here, the compressor CM is continuously driven during the cooling operation of the cooling device 32 and stopped when the cooling device 32 is stopped. The compressor CM and the condenser CD are commonly arranged on the base plate 24 in the machine room 20, and a condenser fan FM for forcibly cooling the condenser CD is also provided on the base plate 24 so as to face the condenser CD. It is arranged. Here, the condenser CD is disposed on the front side of the machine room 20 in the vicinity of the metal panel (front panel) 18 that forms the front surface of the cabinet 16, and the condenser fan FM is disposed on the rear side of the condenser CD. . The compressor CM is disposed on the rear side of the condenser fan FM (see FIG. 2). Thus, in the machine room 20, the condenser CD, the condenser fan FM, and the compressor CM are aligned in a straight line along the flow direction of the air sent out by the condenser fan (blower unit) FM in the machine room 20. Arranged. That is, outside air is taken into the machine room 20 from an air circulation hole (not shown) provided between the front panel 18 and the cabinet 16 by driving the condenser fan FM, and this outside air is moved from the front side of the machine room 20 to the rear side. The heat exchanger exchanges heat with the condenser CD and the compressor CM.

  In the primary circuit 34, the primary refrigerant is forcibly circulated in the order of the compressor CM, the condenser CD, the expansion valve EV, the primary heat exchange section 36 of the heat exchanger HE, and the compressor CM by the compression of the primary refrigerant by the compressor CM. The required cooling is performed in the primary heat exchange section 36 under the action of each device (see FIG. 4). The control electrical box C described above is disposed on the base plate 24 at a position that does not obstruct the air flow by the condenser fan FM in the machine room 20 (side of the machine room 20 in the embodiment). .

  The secondary circuit 44 includes a secondary heat exchange unit 46 of the heat exchanger HE that liquefies the gas phase secondary refrigerant (vaporized refrigerant) and an evaporator EP that vaporizes the liquid phase secondary refrigerant (liquefied refrigerant). The secondary heat exchange unit 46 and the evaporator EP correspond to each other in a one-to-one relationship (see FIG. 4). Further, the secondary circuit 44 includes a liquid pipe 48 and a gas pipe 50 that connect the secondary heat exchange unit 46 and the evaporator EP, and gravity is transferred from the secondary heat exchange unit 46 to the evaporator EP via the liquid pipe 48. Under the action, the liquid phase secondary refrigerant is supplied, and the gas phase secondary refrigerant is recirculated from the evaporator EP to the secondary heat exchange section 46 via the gas pipe 50. Further, the secondary circuit 44 is provided with a preliminary heat exchanging section 54 described later in the gas pipe 50. As described above, the secondary heat exchange unit 46 is disposed in the machine room 20, while the evaporator EP is disposed in the cooling chamber 28 located below the machine room 20 and sandwiches the base plate 24. An evaporator EP is disposed below the secondary heat exchange unit 46.

  The secondary heat exchange unit 46 is provided with a plurality of condensation paths 47 (three in the second embodiment) in parallel. The evaporator EP is provided with a plurality of (three in the embodiment) evaporation pipes (evaporation paths) 52 in parallel. In FIG. 4, the condensing path 47 is represented by a straight path from the inflow end connecting to the gas pipe 50 to the outflow end connecting to the liquid pipe 48, and from the inflow end connecting the evaporation pipe 52 to the liquid pipe 48 to the gas pipe 50. However, the condensation path 47 and the evaporation pipe 52 may be meandered or may be formed in a straight line. Here, in the secondary circuit 44, the plurality of condensation paths 47, the plurality of evaporation pipes 52, the plurality of liquid pipes 48, and the plurality of gas pipes 50 are set to the same number. The liquid pipe 48 is piped through the base plate 24 by connecting the upper end (starting end) to the outflow end of the condensation path 47 in the secondary heat exchange section 46, and the lower end (end) located on the cooling chamber 28 side evaporates. It is connected to the inflow end of the evaporation pipe 52 in the vessel EP. The gas pipe 50 has a lower end (starting end) located on the cooling chamber 28 side connected to the outflow end of the evaporation pipe 52 in the evaporator EP and is piped through the base plate 24 and is located on the machine room 20 side. The upper end (termination) is connected to the inflow end of the condensation path 47 in the secondary heat exchange unit 46 via the preliminary heat exchange unit 54. In addition, the penetration site | part of the base plate 24 in the liquid piping 48 and the gas piping 50 is airtightly sealed with the seal | sticker etc. FIG.

  In the secondary circuit 44, the liquid pipe 48 connected to the outflow end of the condensation path 47 is connected to the evaporation pipe 52 connected to the gas pipe 50 connected to the inflow end of the condensation path 47 and another evaporation pipe 52. Configured to do. In the secondary circuit 44, the gas pipe 50 connected to the outflow end of the evaporation pipe 52 is connected to the condensation path 47 connected to the liquid pipe 48 connected to the inflow end of the evaporation pipe 52 and another condensation path 47. is doing. As described above, the secondary circuit 44 includes a plurality of (three in the embodiment) paths that are pseudo-parallel by the plurality of condensation paths 47, the plurality of evaporation pipes 52, the plurality of liquid pipes 48, and the plurality of gas pipes 50. However, these paths are serially connected to form one circuit as a whole. In the secondary circuit 44, a temperature gradient is formed between the secondary heat exchange unit 46 cooled by heat exchange with the primary heat exchange unit 36 that is forcibly cooled and the evaporator EP, and the secondary refrigerant is A refrigerant circulation cycle is formed in which the secondary heat exchange section 46, the liquid pipe 48, the evaporator EP, and the gas pipe 50 are naturally convected and returned to the secondary heat exchange section 46 again. Here, the preliminary heat exchange units 54 are respectively provided in the gas pipes 50 connected to the respective condensation paths 47 corresponding to the plurality of condensation paths 47 in the secondary heat exchange unit 46. Reference numeral 74 denotes a refrigerant charge port provided for charging the secondary circuit 44 with the refrigerant. Since the secondary circuit 44 of the embodiment is configured by a single circuit, the refrigerant charge port 74 is provided. A single set of incidental facilities such as a safety valve (not shown) is sufficient.

  The evaporator EP is composed of an evaporation pipe 52 having meandering pipe lines and fins 53 provided on the evaporation pipe 52. The evaporating pipe 52 has an inflow end connected to the lower end of the liquid pipe 48 disposed below the evaporator EP, and an outflow end of the evaporating pipe 52 connected to the lower end of the gas pipe 50 located above the evaporator EP. It arrange | positions and it is comprised so that the inflow end of the evaporation pipe | tube 52 may be located below an outflow end (refer FIG. 4). The pipe of the evaporation pipe 52 extends between the upper and lower positions of the inflow end and the outflow end, and the liquid secondary refrigerant flowing into the evaporation pipe 52 is subjected to the action of evaporation of the liquid phase secondary refrigerant. It is guided so as to be diffused along the pipe line to the outflow end 52b side.

  The heat exchanger HE of the embodiment will be specifically described. As shown in FIG. 3 or FIG. 5, the heat exchanger HE has a tubular secondary heat exchange portion 46 made of a metal material having excellent heat conductivity as an inner tube, and the outside of the secondary heat exchange portion 46 is primary. A double-pipe heat exchanger having an outer pipe serving as a primary heat exchanging portion 36 that covers a refrigerant circulation space, and is configured to cover three condensing paths 47 in parallel with the primary heat exchanging portion 36. Is done. In addition, the primary heat exchange part 36 is comprised with a metal material. Further, the heat exchanger HE is arranged such that the condensation path 47 of the secondary heat exchange unit 46 arranged in parallel extends in a spiral shape with the vertical direction as an axis, and covers the outside of the condensation path 47. The primary heat exchanging part 36 is configured to extend in a spiral manner like the secondary heat exchanging part 46. That is, the heat exchanger HE is a spiral tubular body configured so as to draw a ring on a plane (see FIG. 2), and a preliminary heat exchange section is provided at the upper end of each condensation path 47 in the secondary heat exchange section 46. A gas pipe 50 is connected via 54, and a liquid pipe 48 is connected to the lower end of each condensing path 47 so that the secondary refrigerant flows through the condensing path 47 from above to below while spiraling along a spiral shape. It has become. On the other hand, the primary heat exchange unit 36 has an inflow side refrigerant pipe 38 connected to the expansion valve EV connected to the lower end, and an outflow side refrigerant pipe 38 connected to the compressor CM connected to the upper end. The primary refrigerant circulates in the circulation space of the primary heat exchange section 36 from below to above while spiraling along the spiral shape. That is, in the heat exchanger HE, the flow direction of the secondary refrigerant flowing through each condensation path 47 of the secondary heat exchange unit 46 and the flow direction of the primary refrigerant flowing through the primary heat exchange unit 36 are opposed to each other. Configured to be.

  The heat exchanger HE is disposed above the compressor CM in the machine room 20, and is disposed so that the compressor CM faces the ring formed by the heat exchanger HE (see FIG. 1 or FIG. 2). ). The heat exchanger HE is disposed in the machine room 20 at a position lower than the top of the condenser CD, which is taller than the compressor CM, and does not protrude from the machine room 20. Further, the heat exchanger HE is arranged on the downstream side in the flow direction of the air sent by the condenser fan FM, and is located on the path of the air flow sent by the condenser fan FM. The heat exchanger HE is formed in a spiral shape and has a long path through which the refrigerant flows in the lateral direction, and the dimension in the upper and lower overlapping directions is reduced to form a horizontally elongated shape as a whole.

  As shown in FIG. 4, the secondary circuit 44 is provided with a preliminary heat exchange section 54 in the gas pipe 50, and the preliminary heat exchange section 54 circulates through the gas pipe 50 in the primary circuit 34 or the secondary circuit 44. It is configured to be cooled by contacting with a part having a temperature lower than that of the gas phase secondary refrigerant. The preliminary heat exchanging portion 54 of the embodiment is arranged so as to contact the primary heat exchanging portion 36 that constitutes the outline of the heat exchanger HE, and the primary heat exchanging portion 36 that is cooled under the operation of each device of the primary circuit 34. As a cooling means. That is, the preliminary heat exchange unit 54 can cool the gas phase secondary refrigerant flowing therein before flowing into the secondary heat exchange unit 46 of the heat exchanger HE.

  The preliminary heat exchanging part 54 is a tubular body made of a metal material having excellent heat conductivity, and is provided along the primary heat exchanging part 36 extending spirally so as to be brought into contact with the primary heat exchanging part 36. Are arranged. Note that the flow direction of the secondary refrigerant in the preliminary heat exchange unit 54 is an opposite flow in the opposite direction to the primary refrigerant flowing through the primary heat exchange unit 36. In the secondary circuit 44 of the embodiment, the preliminary heat exchange sections 54 are provided corresponding to the three paths, respectively, and the three preliminary heat exchange sections 54 are arranged in parallel and extend in a spiral shape with the vertical direction as an axis. It is configured as follows. That is, in the cooling device 32 of the embodiment, the preliminary heat exchanging portion 54 is located lower than the top of the condenser CD and is disposed on the upper side of the compressor CM like the heat exchanger HE, and is formed by the preliminary heat exchanging portion 54. The compressor CM faces the ring. The preliminary heat exchange unit 54 is cooled in contact with the primary heat exchange unit 36 that is cooled by the circulating primary refrigerant, and takes sensible heat from the gas phase secondary refrigerant that circulates inside. Further, the preliminary heat exchange unit 54 is configured such that the flow path of the secondary refrigerant in the preliminary heat exchange unit extends longer than the shortest distance connecting the inflow end and the outflow end, and the preliminary heat exchange with the gas pipe 50 is performed. Compared to the case where the portion 54 is not provided, the internal volume of the secondary circuit 44 is increased by the volume of the preliminary heat exchange portion 54. In addition, the heat exchanger HE and the preliminary heat exchange part 54 are covered with a heat insulating material (not shown) in a portion exposed to the outside, and heat insulation measures are taken.

  In the heat exchanger HE, the primary refrigerant flowing through the primary heat exchange unit 36 is in direct contact with each condensation path 47 of the secondary heat exchange unit 46, and thus has excellent heat exchange efficiency. On the other hand, the preliminary heat exchanging unit 54 is configured such that the outer surface of the preliminary heat exchanging unit 54 contacts the outer surface of the primary heat exchanging unit 36 constituting the outline of the heat exchanger HE. The primary heat exchanging part 36 and the preliminary heat exchanging part 54 cooled by the primary refrigerant that circulates 36 exchange heat by contact heat transfer, and further, the gas phase two that circulates between the preliminary heat exchanging part 54 and the preliminary heat exchanging part 54. The secondary refrigerant exchanges heat. Here, although the preliminary heat exchange unit 54 cools the gas phase secondary refrigerant by contact with the heat exchanger HE (primary heat exchange unit 36), the purpose of the cooling degree is to deprive the sensible heat of the secondary refrigerant. The phase change of the secondary refrigerant is not caused without heat exchange due to latent heat. That is, the preliminary heat exchanging unit 54 has a thermal conductivity by selecting a contact area with the primary heat exchanging unit 36, a material and a thickness of the preliminary heat exchanging unit, etc. according to the cooling performance of the primary heat exchanging unit 36 serving as a cooling means. These conditions are adjusted as appropriate.

(Effects of Example)
Next, the operation of the cooling device 32 according to the embodiment will be described. In the cooling device 32, when the cooling operation is started, circulation of the refrigerant is started in each of the primary circuit 34 and the secondary circuit 44. First, the primary circuit 34 will be described. The compressor CM and the condenser fan FM are driven, the gas-phase primary refrigerant is compressed by the compressor CM, and this primary refrigerant is supplied to the condenser CD via the refrigerant pipe 38. The liquid phase is obtained by condensing and liquefying by forced cooling by the condenser fan FM. The liquid phase primary refrigerant is decompressed by the expansion valve EV, and in the primary heat exchanging portion 36 of the heat exchanger HE, heat is taken from the secondary refrigerant flowing through the secondary heat exchanging portion 46 (heat absorption) and is vaporized at once. Thus, the primary circuit 34 functions to forcibly cool the secondary heat exchange unit 46 by the primary heat exchange unit 36 in the heat exchanger HE. Then, the gas phase primary refrigerant vaporized in the primary heat exchange unit 36 repeats the forced circulation cycle that returns to the compressor CM through the refrigerant pipe 38.

  In the secondary circuit 44, since the secondary heat exchange unit 46 is cooled by the primary heat exchange unit 36, the secondary heat exchange unit 46 radiates and condenses the gas phase secondary refrigerant, and the liquid phase from the gas phase Since the specific gravity increases due to the state change, the liquid secondary refrigerant flows down along the secondary heat exchange section 46 under the action of gravity. In the secondary circuit 44, the secondary heat exchange unit 46 is arranged in the machine room 20, while the evaporator EP is arranged in the cooling chamber 28 located below the machine room 20, so that the secondary heat exchange unit 46 and A head is provided with the evaporator EP. That is, the liquid phase secondary refrigerant can be naturally flowed under the action of gravity toward the evaporator EP via the liquid pipe 48 connected to the lower portion of the secondary heat exchange section 46. The liquid secondary refrigerant is vaporized by taking heat from the ambient atmosphere of the evaporator EP in the process of flowing through the evaporation pipe 52 of the evaporator EP, and is transferred to the gas phase. The gas phase secondary refrigerant flows back from the evaporator EP to the secondary heat exchange unit 46 via the gas pipe 50 and the preliminary heat exchange unit 54, and the secondary circuit 44 is simple without using power from a pump, a motor, or the like. A cycle in which the secondary refrigerant naturally circulates in a simple configuration is repeated.

  By blowing the air in the storage chamber 14 sucked into the cooling chamber 28 from the suction port 26a by the blower fan 30 onto the cooled evaporator EP, the air heat-exchanged with the evaporator EP becomes cold air. The storage chamber 14 is cooled by sending the cool air from the cooling chamber 28 to the storage chamber 14 via the cool air outlet 26b. The cold air circulates inside the storage chamber 14 and repeats a cycle of returning to the cooling chamber 28 again through the suction port 26a.

  In the cooling device 32, in the secondary circuit 44, the gas phase secondary refrigerant flowing through the preliminary heat exchange unit 54 is cooled by heat exchange with the primary heat exchange unit 36 in the preliminary heat exchange unit 54 provided in the gas pipe 50. By doing so, it is in a saturated state in which the degree of superheat and the degree of dryness are reduced as compared with the time when the gas phase secondary refrigerant flows out of the evaporator EP. Further, since the superheat degree and the dryness of the gas phase secondary refrigerant flowing into each condensation path 47 of the secondary heat exchange unit 46 are previously reduced in the preliminary heat exchange part 54, the inflow end side of the condensation path 47 From this, an annular flow can be formed immediately, and loss of heat transfer area can be suppressed. That is, in the heat exchanger HE, the heat transfer area between the primary heat exchange unit 36 and the secondary heat exchange unit 46 is utilized to the maximum extent, and the entire primary heat exchange unit 36 and the secondary heat exchange unit 46 are used. Thus, heat exchange can be performed efficiently. Even when the cooling load is large, the cooling device 32 preliminarily cools the gas phase secondary refrigerant by the preliminary heat exchange unit 54 and reduces the superheat degree of the gas phase secondary refrigerant in advance. It is possible to narrow the increase in the degree of superheat that the gas-phase secondary refrigerant flowing into the exchange unit 46 fluctuates due to an increase in the cooling load. Thus, the cooling device 32 can suppress fluctuations in the heat exchange efficiency in the heat exchanger HE even if the cooling load fluctuates, and enlarges the weight by making the heat exchanger HE correspond to the cooling load, weight, The system can be stabilized without increasing volume and cost.

  The heat exchanger HE is cooled by the primary refrigerant flowing inside the primary heat exchanging section 36 and becomes cooler than the ambient temperature. Therefore, the heat exchanger HE is covered with the heat insulating material as described above for the purpose of reducing the heat dissipation loss of the cooling capacity. This is a configuration. In the cooling device 32, as the cooling means for cooling the preliminary heat exchanging portion 54, the primary heat exchanging portion 36 that constitutes the outline of the heat exchanger HE is used, and cooling to be insulated in order to prevent heat dissipation loss in the heat exchanger HE. The capacity is used as a cooling source for the preliminary heat exchanger 54. That is, the cooling device 32 can recover the cooling capacity that may be lost as a heat dissipation loss of the heat exchanger HE during the refrigerant circulation cycle, and can further improve the heat exchange efficiency in the heat exchanger HE. . In addition, since the difference between the surface of the heat exchanger HE (primary heat exchanging portion 36) and the ambient temperature becomes small, it is possible to simplify heat insulation measures such as the thickness and type of the heat insulating material.

  When the compressor CM is stopped due to the operation stop of the cooling device 32 or the like, heat exchange in the heat exchanger HE by the primary refrigerant is stopped. At this time, in the secondary circuit 44, the liquid phase secondary refrigerant is vaporized in the evaporator EP to generate the gas phase secondary refrigerant, while the gas phase secondary refrigerant is not liquefied in the heat exchanger HE. The amount of the gas phase secondary refrigerant in the secondary circuit 44 increases, and the internal pressure of the secondary circuit 44 increases. Here, in order to increase the contact area with the primary heat exchange unit 36, the preliminary heat exchange unit 54 circulates the preliminary heat exchange unit 54 from the shortest distance connecting the inflow end and the outflow end of the preliminary heat exchange unit 54. Since the path is set to extend long, the internal volume of the secondary circuit 44 is increased by the amount of the preliminary heat exchange unit 54 as compared with the case where the gas pipe 50 is directly connected to the secondary heat exchange unit 46. ing. Further, in the preliminary heat exchange unit 54, the amount of heat exchange with the primary heat exchange unit 36 from the heat exchanger HE is the contact heat transfer between the outer surface of the preliminary heat exchange unit 54 and the outer surface of the primary heat exchange unit 36. The secondary refrigerant is adjusted to be small and the secondary refrigerant is not completely condensed and liquefied.

  By the way, the function of the expansion tank is to buffer the high pressure of the secondary refrigerant in the secondary circuit 44 by the volume. This is because the volume of the secondary circuit 44 increases due to the presence of the expansion tank, and its volume. The effectiveness of the function is determined by the balance of the amount of secondary refrigerant that is additionally required to fill the interior with the secondary refrigerant. For example, if the refrigerant density in the expansion tank is large and the amount of refrigerant that increases due to the presence of the refrigerant is large, the pressure value that must be buffered by the increase in the amount of carbon dioxide refrigerant increases. With the added volume, the pressure increase cannot be absorbed, and the required value of the pressure resistance design becomes higher. In this case, the installation of the expansion tank has an adverse effect on the pressure buffering. That is, a low refrigerant density in the expansion tank during operation of the cooling device 32 is a requirement for developing the function as the expansion tank. The state of the secondary refrigerant in the path of the preliminary heat exchanger 54 is not completely liquefied and condensed as described above because the heat exchange amount in the path is relatively small. That is, the refrigerant density in the path of the preliminary heat exchange unit 54 is low. This is because the pressure value is buffered by adding the volume more than the increase in additional pressure derived from the amount of refrigerant additionally required due to the addition of the volume of the preliminary heat exchanging portion 54. It shows that it becomes. That is, the preliminary heat exchange unit 54 functions as an expansion tank because of the low density of the internal secondary refrigerant. Therefore, by providing the preliminary heat exchange section 54, the expansion tank is not required (Example), or the expansion tank can be reduced in size by reducing the volume of the expansion tank.

  In the cooling device 32, the condenser fan FM has the rotor blade diameter determined by the required air volume, and the size of the condenser CD efficiently exchanges heat with the air flow taken in by the condenser fan FM. Therefore, it is set to be approximately the same as the diameter of the rotor blade. On the other hand, the compressor CM is appropriately determined irrespective of the condenser fan FM and the condenser CD, and the compressor CM is generally smaller than the condenser fan FM and the condenser CD, The height is also lower than the condenser fan FM and the condenser CD. That is, the height of the machine room 20 is determined by the heights of the condenser fan FM and the condenser CD, and a space can be secured above the compressor CM. In the cooling device 32 of the embodiment, the heat exchanger HE and the preliminary heat exchanging unit 54 are arranged in the space above the compressor CM. Therefore, the machine room 20 can be made compact by effectively using the space.

  The secondary circuit 44 is configured to cause the secondary refrigerant liquefied by the secondary heat exchange unit 46 to flow down to the evaporator EP via the liquid pipe 48 under the action of gravity, as described above. It is necessary to ensure a drop between the secondary heat exchange unit 46 and the evaporator EP. In the cooling device 32, the heat exchanger HE is positioned above the machine room 20 by disposing the heat exchanger HE on the upper side of the compressor. Therefore, the cooling chamber 28 provided below the machine room 20. It is possible to ensure a large drop with respect to the evaporator EP arranged in the. As a result, in the secondary heat exchanging section 46, the potential energy, which is one of the driving forces that cause the secondary refrigerant to naturally flow down toward the evaporator EP, increases, and the secondary refrigerant is smoothly circulated in the secondary circuit 44. Cooling capacity can be improved. Furthermore, the heat exchanger HE is disposed on the downstream side in the flow direction of the air sent by the condenser fan FM and is located on the path of the air flow sent by the condenser fan FM. Since the air flow heated by exchanging heat with the condenser CD is brought into contact with the drive, dew condensation and frost formation in the heat exchanger HE can be suppressed, and heat insulation measures can be reduced. Moreover, it is easy to connect the liquid pipe 48 and the preliminary heat exchanging portion 54 to the heat exchanger HE and the gas pipe 50 to the preliminary heat exchanging portion 54, and maintainability of the heat exchanger HE and the preliminary heat exchanging portion 54. Can improve.

(Example of change)
The cooling device according to the present invention is not limited to the above-described embodiment, and various modifications can be made.

(1) FIG. 6 is a side sectional view showing a refrigerator according to a modified example. The refrigerator 11 of the modified example includes a condenser CD, a condenser fan FM, a compressor CM, an expansion valve EV as a decompression means, and an evaporator EP and a blower fan on the side of the machine room 20 where the heat exchanger HE is installed. The cooling chamber 28 in which 30 is installed is provided. Even in the refrigerator of the modified example, the heat exchanger HE is arranged on the upper side of the compressor CM as in the embodiment, so that the heat exchange is performed even if the evaporator EP is arranged on the side of the machine room 20. The head between the evaporator HE and the evaporator EP can be ensured. In FIG. 6, the same members and structures as those described in the embodiment are denoted by the same reference numerals.

(2) The cooling means for cooling the preliminary heat exchange unit is not limited to the heat exchanger (primary heat exchange unit), and appropriate parts of the primary circuit and the secondary circuit can be adopted. For example, as shown in FIG. 7A, a refrigerant pipe 38 that connects the primary heat exchange unit 36 and the compressor CM in the primary circuit 34 is brought into contact with the preliminary heat exchange unit 54 and used as a cooling means. 7 (b), the refrigerant pipe 38 connecting the expansion valve EV as the pressure reducing means in the primary circuit 34 and the primary heat exchanging section 36 is brought into contact with the preliminary heat exchanging section 54 and used as the cooling means. May be. Moreover, as shown in FIG.7 (c), the structure which makes the liquid piping 48 of the secondary circuit 44 contact the preliminary | backup heat exchange part 54, and uses it as a cooling means may be sufficient. As a cooling means for cooling the preliminary heat exchange unit 54, the heat exchanger HE, the primary heat exchange unit 36, the low-pressure side pipe of the primary circuit 34, and the liquid pipe 48 of the secondary circuit 44 may be used in combination. In addition, the primary circuit is provided with a bypass pipe that branches from the refrigerant pipe connecting the condenser and the expansion valve and is connected to the compressor via another decompression means, and this bypass pipe is in contact with the preliminary heat exchange section. There may be. In FIG. 7, the same members and structures as those described in the embodiment are denoted by the same reference numerals. In FIG. 7, the hatched portion indicates the heat exchange site between the preliminary heat exchange unit 54 and the cooling means.

(3) The heat exchanger is not limited to the double tube heat exchanger as in the embodiment, but is a spiral heat exchanger, a plate heat exchanger, a multi-tube cylindrical heat exchanger, a multi-tube heat exchanger. A heat exchanger, a spiral tube heat exchanger, a spiral plate heat exchanger, a tank coil heat exchanger, a tank jacket heat exchanger, and the like can be employed.
(4) In the embodiment, the case where the cooling device is employed in the refrigerator has been described as an example.
(5) In the embodiment, the storage chamber and the machine room are separated from each other by a base plate serving as a common substrate for equipment disposed in the machine room so that there is no air flow between the machine room and the storage room. However, the machine room and the storage room may be separated by a box top plate.
(6) In the embodiment, the expansion valve is used as the pressure reducing means of the primary circuit, but a capillary tube or other means can be adopted.

It is side sectional drawing which shows the refrigerator cooled with the cooling device which concerns on the Example of this invention. It is a top view which shows the machine room in the refrigerator which concerns on an Example. It is a side view which shows the heat exchanger which concerns on an Example partially broken. It is a schematic circuit diagram which shows the cooling device which concerns on an Example. It is the sectional view on the AA line of FIG. It is a sectional side view which shows the refrigerator of the example of a change. It is a schematic circuit diagram which shows the cooling device of the example of a change. It is a schematic circuit diagram which shows the conventional cooling device.

Explanation of symbols

20 machine room, 34 primary circuit, 36 primary heat exchange section, 44 secondary circuit (refrigerant circuit),
46 Secondary heat exchange section (heat exchange section), 48 liquid piping, 50 gas piping, 54 preliminary heat exchange section,
CM compressor, EV expansion valve (pressure reduction means), EP evaporator, HE heat exchanger

Claims (7)

A heat exchange section (46) that condenses the gas-phase refrigerant to form a liquid-phase refrigerant, and an evaporator (EP) that vaporizes the liquid-phase refrigerant to form a gas-phase refrigerant include a liquid pipe (48) and a gas pipe (50 ), The liquid phase refrigerant is circulated from the heat exchange section (46) to the evaporator (EP) through the liquid pipe (48), and the vapor phase refrigerant is circulated through the gas pipe (50). ) In the cooling device configured with the refrigerant circuit (44) that circulates from the heat exchange section (46),
Preliminary heat for cooling the gas pipe (50) connecting the evaporator (EP) and the heat exchanging section (46) before flowing the gas-phase refrigerant flowing therethrough into the heat exchanging section (46). A cooling device provided with an exchange part (54). A primary circuit (34) forcibly circulating a primary refrigerant mechanically by a compressor (CM);
The refrigerant circuit (44) as a secondary circuit for naturally circulating the secondary refrigerant;
A primary heat exchange section (36) of the primary circuit (34) and a heat exchange section (46) of the refrigerant circuit (44) are provided, and a primary refrigerant and a heat exchange section (circulating through the primary heat exchange section (36)) ( 46) and a heat exchanger (HE) for exchanging heat between secondary refrigerants flowing through
The cooling device according to claim 1, wherein the preliminary heat exchange section (54) is disposed so as to contact an outer surface of the heat exchanger (HE).   The heat exchanger (HE) opens a circulation space for primary refrigerant outside the heat exchange section (46) whose lower end is connected to the liquid pipe (48) and whose upper end is connected to the gas pipe (50). The cooling device according to claim 2, wherein the primary heat exchanging portion (36) is covered with the primary heat exchanging portion (36), and the primary heat exchanging portion (36) is an outer shell of the heat exchanger (HE). A primary circuit (34) forcibly circulating a primary refrigerant mechanically by a compressor (CM);
The refrigerant circuit (44) as a secondary circuit for naturally circulating the secondary refrigerant;
A primary heat exchange section (36) of the primary circuit (34) and a heat exchange section (46) of the refrigerant circuit (44) are provided, and a primary refrigerant and a heat exchange section (circulating through the primary heat exchange section (36)) ( 46) and a heat exchanger (HE) for exchanging heat between secondary refrigerants flowing through
The preliminary heat exchange section (54) is a part of the primary circuit (34) from the decompression means (EV) in the primary circuit (34) to the compressor (CM) via the primary heat exchange section (36). The cooling device according to claim 1, wherein the cooling device is configured to exchange heat with a low-pressure side pipe.   The preliminary heat exchanging section (54) is configured such that a flow path of the secondary refrigerant extends longer than a shortest path connecting the inflow end and the outflow end of the preliminary heat exchange section (54). The cooling device according to any one of the above.   The said preliminary heat exchange part (54) is a cooling device as described in any one of Claims 1-5 provided in the machine room (20) in which the said heat exchange part (46) is installed.   The cooling device according to any one of claims 1 to 6, wherein the preliminary heat exchange section (54) is configured to exchange heat with the liquid pipe (48).

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