Refrigerator

Abstract

To provide a refrigerator that is structured with a two-step compression cycle and that has high versatility by allowing a total heat radiation of a heat radiator which releases the heat of a compressed refrigerant to be easily adjusted to a heat radiation that is consistent with a required refrigeration capacity.SOLUTION: A refrigerator 11 comprises a front-stage compressor 12, a front-stage heat radiator 13, a rear-stage compressor 14, a rear-stage heat radiator 15, and refrigerator piping 18 for connecting these apparatuses 12 to 15. The front-stage heat radiator 13 is formed of a plurality of unit front-stage heat radiators 13a, 13a which are connected in parallel to the refrigerant piping 18 and have the same amount of heat radiation. The rear-stage heat radiator 15 is formed of a plurality of unit rear-stage heat radiators 15a, 15a which are connected in parallel to the refrigerant piping 18 and have the same amount of heat radiation. By changing the number of unit front-stage heat radiators 13a that form the front-stage heat radiator 13, a total amount of heat radiation of the front-stage heat radiator 13 can be adjusted. Likewise, by changing the number of unit rear-stage heat radiators 15a that form the rear-stage heat radiator 15, a total amount of heat radiation of the rear-stage heat radiator 15 can be adjusted.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a refrigeration system configured with a two-stage compression refrigeration cycle. [Background technology]

[0002] This type of refrigeration device is disclosed in, for example, Patent Document 1 and is publicly known. The refrigeration device described in Patent Document 1 (title of invention: manufacturing method of transcritical refrigeration cycle device) is configured to include a low-stage compression means of a compressor that compresses and discharges a refrigerant, a subcooler that dissipates heat from the intermediate-pressure refrigerant discharged from the low-stage compression means, a high-stage compression means of a compressor that compresses and discharges the intermediate-pressure refrigerant that has dissipated heat in the subcooler, and a gas cooler that dissipates heat from the high-pressure refrigerant discharged from the high-stage compression means. The subcooler and the gas cooler are integrated and configured as one fin-tube type heat exchanger. Specifically, the heat exchanger includes a group of fins made of thin plates that promote heat exchange with air, and a heat dissipation pipe that is repeatedly reversed in a serpentine shape and penetrates the group of fins in the thickness direction, and the heat dissipation pipes of the subcooler and the gas cooler are respectively configured as separate pipes, and the fins are shared by the subcooler and the gas cooler. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-263431 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, refrigerators for storing food and the like are prepared in a series of several types with different internal volumes, but the refrigeration capacity required of the refrigeration equipment varies depending on the internal volume. However, if the subcooler and gas cooler are configured with one fin-tube type heat exchanger as in the refrigeration equipment of Patent Document 1, it is necessary to prepare several types of heat exchangers with heat dissipation amounts suitable for the required refrigeration capacity, which lacks versatility.

[0005] The present invention aims to provide a highly versatile refrigeration device that is configured with a two-stage compression refrigeration cycle and that can easily adjust the total amount of heat dissipation from a radiator that dissipates heat from a compressed refrigerant to an amount of heat dissipation suitable for the required refrigeration capacity. [Means for solving the problem]

[0006] The refrigeration system 11 of the present invention includes a front-stage compressor 12 that compresses and discharges a low-pressure refrigerant evaporated in an evaporator 17, a front-stage radiator 13 that radiates heat from the intermediate-pressure refrigerant discharged from the front-stage compressor 12, a rear-stage compressor 14 that compresses and discharges the intermediate-pressure refrigerant that has had heat radiated in the front-stage radiator 13, a rear-stage radiator 15 that radiates heat from the high-pressure refrigerant discharged from the rear-stage compressor 14, and a refrigerant pipe 18 to which the front-stage compressor 12, the front-stage radiator 13, the rear-stage compressor 14, and the rear-stage radiator 15 are connected. The front-stage radiator 13 is composed of a plurality of unit front-stage radiators 13a·13a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18, and the rear-stage radiator 15 is composed of a plurality of unit rear-stage radiators 15a·15a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18. Furthermore, the present invention is characterized in that the total amount of heat dissipation of the front stage radiators 13 can be adjusted by changing the number of unit front stage radiators 13a, and the total amount of heat dissipation of the rear stage radiators 15 can be adjusted by changing the number of unit rear stage radiators 15a.

[0007] The system includes a plurality of radiator units 50, each of which is composed of a radiator pair 43 formed by arranging one unit front-stage radiator 13a and one unit rear-stage radiator 15a adjacent to each other in the front-rear direction, and a cooling fan 49 that supplies a cooling air flow to the radiator pair 43. In each radiator pair 43, the unit front-stage radiator 13a is disposed upstream of the air flow, and the unit rear-stage radiator 15a is disposed downstream of the air flow.

[0008] The front-stage radiator unit 13a and the rear-stage radiator unit 15a are each composed of a fin-tube type heat exchanger 34 including a group of fins 35 made of thin plates arranged in parallel in the left-right direction, and a heat dissipation tube 36 that is repeatedly turned over in a serpentine shape and penetrates the group of fins 35 in the thickness direction. The heat dissipation tube 36 is formed from a single seamless pipe material.

[0009] The group of fins 35 of the unit front-stage radiator 13a and the group of fins 35 of the unit rear-stage radiator 15a are arranged at equal pitches, and the adjacent pitch P1 of the fins 35 of the unit front-stage radiator 13a and the adjacent pitch P2 of the fins 35 of the unit rear-stage radiator 15a are set to the same pitch. When the radiator pair 43 is viewed from the front, the unit front-stage radiator 13a and the unit rear-stage radiator 15a are arranged adjacent to each other in the front-rear direction so that the fins 35 of the unit front-stage radiator 13a and the fins 35 of the unit rear-stage radiator 15a overlap. Effect of the Invention

[0010] In the refrigeration device 11 of the present invention, when the front-stage radiator 13 is composed of a plurality of unit front-stage radiators 13a·13a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18, the temperatures of the intermediate-pressure refrigerant that joins after passing through each unit front-stage radiator 13a can be made substantially uniform, so that the refrigerant can be smoothly circulated by preventing refrigerant flow disturbances that occur when intermediate-pressure refrigerants with different temperatures join. Similarly, when the rear-stage radiator 15 is composed of a plurality of unit rear-stage radiators 15a·15a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18, the temperatures of the high-pressure refrigerant that joins after passing through each unit rear-stage radiator 15a can be made substantially uniform, so that the refrigerant can be smoothly circulated by preventing refrigerant flow disturbances that occur when high-pressure refrigerants with different temperatures join. As described above, according to the refrigeration device 11 of the present invention, even though each of the front-stage radiator 13 and the rear-stage radiator 15 is composed of a plurality of unit radiators 13a·15a, it is possible to prevent refrigerant circulation from being adversely affected.

[0011] In addition, as in the refrigeration device 11 of the present invention, if the total amount of heat radiation of the front stage radiators 13 can be adjusted by changing the number of unit front stage radiators 13a, and the total amount of heat radiation of the rear stage radiators 15 can be adjusted by changing the number of unit rear stage radiators 15a, the total amount of heat radiation of the radiators 13·15 can be adjusted more easily. In addition, there is no need to prepare a plurality of types of unit radiators with different heat radiation amounts. By preparing one type of unit radiators 13a·15a and simply changing the number of units, the total amount of heat radiation of the radiators 13·15 can be quantitatively increased or decreased. As described above, according to the present invention, a refrigeration device 11 with excellent versatility can be obtained, in which the total amount of heat radiation of the radiators can be easily adjusted to a heat radiation amount suitable for the required refrigeration capacity.

[0012] When multiple unit front-stage radiators with the same heat dissipation capacity that constitute the front-stage radiators are connected in series to the refrigerant piping, there is no refrigerant confluence and therefore no disturbance in the refrigerant flow occurs, but since the refrigerant temperatures flowing into each unit front-stage radiator are different, the degree of heat dissipation of the refrigerant after heat dissipation in each unit front-stage radiator is also different. Therefore, even if the number of unit front-stage radiators is changed, the total amount of heat dissipation of the front-stage radiators cannot be quantitatively increased or decreased, making it difficult to adjust the refrigeration capacity of the refrigeration device 11. The same is true for the rear-stage radiators.

[0013] The system is provided with a plurality of radiator units 50, each of which is composed of a radiator pair 43 formed by arranging one unit front-stage radiator 13a and one unit rear-stage radiator 15a adjacent to each other in the front-to-rear direction, and a cooling fan 49 that supplies a cooling air flow to the radiator pair 43. In each radiator pair 43, the unit front-stage radiator 13a is arranged upstream of the air flow, and the unit rear-stage radiator 15a is arranged downstream of the air flow. According to this, the cooling air exchanges heat with the unit front-stage radiator 13a in which an intermediate-pressure refrigerant with a relatively low refrigerant temperature circulates, and then exchanges heat with the unit rear-stage radiator 15a in which a high-pressure refrigerant with a relatively high refrigerant temperature circulates, so that the temperature difference between the cooling air before heat exchange and the unit front-stage radiator 13a and the temperature difference between the cooling air whose temperature has increased through heat exchange with the unit front-stage radiator 13a and the unit rear-stage radiator 15a can be made large, thereby improving the heat exchange efficiency in both radiators 13a and 15a. Conversely, if the unit rear-stage radiator 15a is arranged on the upstream side of the air flow and the unit front-stage radiator 13a is arranged on the downstream side of the air flow, the temperature difference between the cooling air whose temperature has increased through heat exchange with the unit rear-stage radiator 15a and the unit front-stage radiator 13a becomes small, and it is inevitable that the heat exchange efficiency of the unit front-stage radiator 13a located downstream will decrease.

[0014] When the unit front-stage radiator 13a and the unit rear-stage radiator 15a are configured as a fin-tube type heat exchanger 34 including a group of fins 35 made of thin plates arranged in parallel in the left-right direction and a heat radiation pipe 36 that is repeatedly reversed in a serpentine shape and penetrates the group of fins 35 in the thickness direction, and the heat radiation pipe 36 is formed of a single seamless pipe material, the risk of refrigerant leakage can be reduced and the reliability of the refrigeration device 11 can be improved compared to a configuration in which a joint portion is formed on the heat radiation pipe 36 by welding. This configuration is particularly suitable for a refrigeration device 11 that uses a refrigerant with a high operating pressure, for example, a refrigeration device 11 that uses carbon dioxide as a refrigerant.

[0015] When the adjacent pitch P1 of the fins 35 of the unit front-stage radiator 13a and the adjacent pitch P2 of the fins 35 of the unit rear-stage radiator 15a are set to the same pitch, the ventilation resistance of the cooling air can be made uniform over the entire left-right direction, and it is possible to prevent a decrease in heat exchange efficiency due to a partially large ventilation resistance. Also, when the unit front-stage radiator 13a and the unit rear-stage radiator 15a are arranged adjacent to each other in the front-rear direction so that the fins 35 of the unit front-stage radiator 13a and the fins 35 of the unit rear-stage radiator 15a overlap when the radiator pair 43 is viewed from the front, the cooling air that has passed between the fins 35 of the unit front-stage radiator 13a can be made to flow smoothly between the fins 35 of the unit rear-stage radiator 15a, and it is possible to prevent a vortex or the like from occurring in the intake air flow for cooling, and a decrease in the heat exchange efficiency between the fins 35 and the cooling air. [Brief description of the drawings]

[0016] [Figure 1] 1 is a cross-sectional plan view showing a machine section of a refrigerator to which a refrigeration device according to an embodiment of the present invention is applied; [Diagram 2] FIG. 2 is a vertical cross-sectional side view showing the entire cooling box. [Diagram 3] FIG. 1 is a configuration diagram of a refrigeration device. [Figure 4] FIG. 2 is a cross-sectional plan view showing the radiator unit. [Diagram 5] FIG. [Figure 6] 6 is a cross-sectional view taken along line AA in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] (Embodiment) Fig. 1 to Fig. 6 show an embodiment in which the present invention is applied to a refrigerator. In this embodiment, front, rear, left, right, and up and down are indicated by crossed arrows shown in Fig. 1 and Fig. 2 and the indications of front, rear, left, right, and up and down written near each arrow. In Fig. 2, the refrigerator is configured as a reach-in type showcase, and includes a case body 1 made of a heat-insulating box having an opening on the front side, and a door 2 for opening and closing the opening of the case body 1. The interior 3 surrounded by the case body 1 and the door 2 is divided into a display room 5 and a ventilation duct 6 by a partition plate 4 provided at the top of the interior 3. In the display room 5 facing the door 2, shelves 7 for placing food to be displayed are installed in multiple levels. An interior fan 8 for circulating air in the interior 3 is provided at the entrance of the ventilation duct 6.

[0018] The interior 3 of the refrigerator is cooled by a refrigeration device 11 that uses carbon dioxide as a refrigerant. As shown in Fig. 3, the refrigeration device 11 includes a front-stage compressor 12 that compresses and discharges a low-pressure refrigerant, an intercooler (front-stage radiator) 13 that radiates heat from the intermediate-pressure refrigerant discharged from the front-stage compressor 12, a rear-stage compressor 14 that compresses and discharges the intermediate-pressure refrigerant whose heat has been radiated in the intercooler 13, a gas cooler (rear-stage radiator) 15 that radiates heat from the high-pressure refrigerant discharged from the rear-stage compressor 14, an expansion structure 16 that adiabatically expands the high-pressure refrigerant whose heat has been radiated in the gas cooler 15, an evaporator 17 that evaporates the low-pressure refrigerant decompressed in the expansion structure 16, and the like. These devices (front-stage compressor 12, intercooler 13, rear-stage compressor 14, gas cooler 15, expansion structure 16, and evaporator 17) are connected in a loop by refrigerant piping 18, and among these devices, the front-stage compressor 12, intercooler 13, rear-stage compressor 14, gas cooler 15, and expansion structure 16 are installed in a machine compartment 21 formed above the case body 1, and the evaporator 17 is installed in the ventilation duct 6 together with the above-mentioned internal fan 8 (see FIG. 2). The heat exchanger constituting the evaporator 17 is a known fin-tube type heat exchanger.

[0019] As shown in Figs. 1 and 2, the machine compartment 21 is defined by side panels 23, 23 on both the left and right sides that form the left and right walls of the case body 1 and extend above the ceiling wall 22 of the case body 1, and a front panel 24 that is hung between the front ends of the extended parts of the side panels 23, and has openings on the top and rear surfaces. The front panel 24 is detachably attached. In Fig. 1, reference numeral 25 denotes an air vent provided in the front panel 24, and air can be taken into the machine compartment 21 from the front side of the showcase through this air vent 25. The air vent 25 is made of slits that are formed in parallel in the vertical direction and extend left and right. The front compressor 12, the intermediate cooler 13, the rear compressor 14, the gas cooler 15, the expansion structure 16, and the like are fixed to the ceiling wall 22 and installed in the machine compartment 21.

[0020] As shown in FIG. 3, the front-stage compressor 12 and the rear-stage compressor 14 are driven by a motor 27, and these three (front-stage compressor 12, rear-stage compressor 14, and motor 27) are unitized as a compressor unit 28. The expansion structure 16 has two flow paths: a main flow path in which a first expander 29 is provided, and a sub-flow path in which a second expander 30 is provided. The sub-flow path is provided with an on-off valve 31 for opening and closing the flow path upstream of the second expander 30. Each of the expanders 29 and 30 is made of a capillary tube, and the on-off valve 31 is made of a solenoid valve. During operation of the refrigeration device 11, the first expander 29 constantly adiabatically expands the refrigerant to supply the refrigerant, which has been reduced in pressure, to the evaporator 17, and the total amount of the reduced-pressure refrigerant supplied to the evaporator 17 is adjusted by increasing or decreasing the amount of the refrigerant adiabatically expanded by the second expander 30. The amount of refrigerant adiabatically expanded in the second expander 30 is controlled by changing the valve opening rate per unit time of the on-off valve 31 .

[0021] The intercooler 13 is composed of a plurality of unit intercoolers (unit front-stage radiators) 13a, and the gas cooler 15 is composed of a plurality of unit gas coolers (unit rear-stage radiators) 15a. Specifically, as shown in Fig. 3, the intercooler 13 is composed of two unit intercoolers 13a with the same heat radiation amount and connected in parallel to the refrigerant pipe 18. Similarly, the gas cooler 15 is composed of two unit gas coolers 15a with the same heat radiation amount and connected in parallel to the refrigerant pipe 18. The number of unit intercoolers 13a and the number of unit gas coolers 15a are the same.

[0022] The refrigerant pipe 18 is bifurcated between the front compressor 12 and the economizer 13, and the bifurcated refrigerant pipe 18 is joined between the economizer 13 and the rear compressor 14. Two unit economizers 13a are connected in parallel to this branching portion. The refrigerant pipe 18 is bifurcated between the rear compressor 14 and the gas cooler 15, and the bifurcated refrigerant pipe 18 is joined between the gas cooler 15 and the expansion structure 16. Two unit gas coolers 15a are connected in parallel to this branching portion. The number of unit economizers 13a and unit gas coolers 15a may be any number that satisfies the total amount of heat radiation that is suitable for the refrigeration capacity required for the refrigeration device 11. For example, when a refrigeration capacity greater than that of the refrigeration device 11 of this embodiment is required, the number of unit economizers 13a and unit gas coolers 15a may be three or more. The refrigerant pipe 18 needs to be branched according to the number of unit intercoolers 13a and unit gas coolers 15a.

[0023] 4, the unit intercooler 13a and the unit gas cooler 15a are configured with a heat exchanger 34 including a group of fins 35 made of thin plates arranged in parallel in the left-right direction, a heat radiation pipe 36 that is folded back and forth in a serpentine shape and passes through the group of fins 35 in the thickness direction, and a pair of left and right side plates 37, 37 that are provided at each of the left and right ends of the heat radiation pipe 36 and support the heat radiation pipe 36. In other words, the unit intercooler 13a and the unit gas cooler 15a are configured with a fin tube type heat exchanger 34. The heat radiation pipe 36 is formed by bending a single seamless pipe material, and is configured in a seamless shape without any welded joints at the boundary between the straight portion and the reversed portion.

[0024] The fin-tube type heat exchanger 34 in which the heat radiation pipe 36 is made of seamless pipe material has size limitations in its manufacturing method, and it is difficult to increase the size. However, as in the present embodiment, when the economizer 13 is made of a plurality of unit economizers 13a and the gas cooler 15 is made of a plurality of unit gas coolers 15a, the cooling capacity can be ensured by changing the number of unit economizers 13a and unit gas coolers 15a without increasing the size of the economizer 13 and the gas cooler 15. Therefore, it is possible to adopt seamless pipe material without joints as the heat radiation pipe 36 constituting the unit economizers 13a and the unit gas coolers 15a. In addition, when the heat radiation pipe 36 is made of seamless pipe material without joints, the risk of refrigerant leakage at the joints can be eliminated. Therefore, the heat exchanger 34 of the present embodiment is suitable as a heat exchanger for a refrigeration device that uses carbon dioxide, which has a high operating pressure, as a refrigerant.

[0025] As shown in Fig. 5, each side panel 37 is formed in a crank-shaped cross section by a vertical main wall 38, an upper wall 39 extending inward from the upper edge of the main wall 38, and a lower wall 40 extending outward from the lower edge of the main wall 38. The above-mentioned heat dissipation pipe 36 is supported by the main wall 38. When installed in the machine compartment 21, the lower wall 40 of the heat exchanger 34 is fixed to the upper surface of the ceiling wall 22 of the case body 1. The main wall 38 is formed slightly larger than the fins 35, and when the heat exchanger 34 is installed in the machine compartment 21, a gap is formed between the lower ends of the fins 35 and the upper surface of the ceiling wall 22 (see Fig. 6).

[0026] The number of fins 35 of the heat exchanger 34 constituting the unit intercooler 13a is set to be the same as the number of fins 35 of the heat exchanger 34 constituting the unit gas cooler 15a. In addition, the adjacent pitch P1 of the fins 35 of the unit intercooler 13a is set to be the same as the adjacent pitch P2 of the fins 35 of the unit gas cooler 15a. Furthermore, the distance between the left and right side plates 37 of the unit intercooler 13a is set to be the same as the distance between the left and right side plates 37 of the unit gas cooler 15a.

[0027] When the length of the heat radiation pipe 36, the size of the fins 35, and the size of the side plate 37 constituting the unit intercooler 13a are compared with the length of the heat radiation pipe 36, the size of the fins 35, and the size of the side plate 37 constituting the unit gas cooler 15a, the lengths and sizes of the two (13a and 15a) are different. Specifically, as shown in Fig. 6, the heat radiation pipe 36 of the unit intercooler 13a is formed by being folded back and inverted in two rows and eight stages, whereas the heat radiation pipe 36 of the unit gas cooler 15a is formed by being folded back and inverted in four rows and eight stages. The fins 35 correspond to the shape of the heat radiation pipe 36, and although the fins 35 of the unit intercooler 13a and the fins 35 of the unit gas cooler 15a have the same vertical height dimension, the front-rear width dimension of the unit intercooler 13a is relatively smaller than that of the unit gas cooler 15a. Similarly, the side plate 37 corresponds to the shape of the heat dissipation pipe 36, and the side plate 37 of the unit intercooler 13a and the side plate 37 of the unit gas cooler 15a have the same vertical height dimension, but the front-to-rear width dimension of the unit intercooler 13a is relatively smaller and the unit gas cooler 15a is relatively larger. From the above, as shown in Figures 4 and 6, the unit intercooler 13a and the unit gas cooler 15a are formed to have approximately the same horizontal width size, and the unit gas cooler 15a is formed to have a larger front-to-rear width dimension than the unit intercooler 13a. In this way, the unit gas cooler 15a of the gas cooler 15 that dissipates heat from a higher temperature high-pressure refrigerant is configured to dissipate a larger amount of heat than the unit intercooler 13a of the intercooler 13 that dissipates heat from an intermediate-pressure refrigerant.

[0028] As shown in Fig. 1, one unit intercooler 13a constituting the intercooler 13 and one unit gas cooler 15a constituting the gas cooler 15 are disposed adjacent to each other in the front-rear direction to form a heat exchanger pair (heat radiator pair) 43. In each heat exchanger pair 43, the unit intercooler 13a is disposed on the front side, and the unit gas cooler 15a is disposed on the rear side. As shown in Fig. 4, the unit intercooler 13a and the unit gas cooler 15a are disposed adjacent to each other in the front-rear direction such that the fins 35 of the unit intercooler 13a and the fins 35 of the unit gas cooler 15a overlap when the heat exchanger pair 43 is viewed from the front. In addition, since the fins 35 of the unit intercooler 13a and the fins 35 of the unit gas cooler 15a are provided independently, it is possible to prevent a decrease in heat exchange efficiency caused by heat transfer from one fin 35 to the other fin 35.

[0029] As shown in Fig. 6, the heat exchanger pair 43 is installed in the machine compartment 21 with the rear end surface of each side plate 37 of the unit intercooler 13a in close contact with the front end surface of each side plate 37 of the unit gas cooler 15a, and a pair of vertical partition walls 44 are formed at the left and right ends of the heat exchanger pair 43 by the main wall 38 of the unit intercooler 13a and the main wall 38 of the unit gas cooler 15a. Also, as shown in Figs. 5 and 6, flat upper partition walls 45 are fixed to the left and right upper walls 39 of the unit intercooler 13a and the upper surfaces of the left and right upper walls 39 of the unit gas cooler 15a. These upper partition walls 45, the upper surface of the ceiling wall 22, and the left and right vertical partition walls 44 form a duct 46 extending in the front-rear direction, dividing the upper and lower and left and right. The fins 35 of the unit intercooler 13a and the unit gas cooler 15a are disposed in the duct 46.

[0030] 4 and 6, a rear partition 47 having two exhaust ports 48, one on the left and one on the right, is fixed to the rear opening of the duct 46. A cooling fan 49, which is an axial fan, is fixed to the rear partition 47 so as to face each exhaust port 48. The heat exchanger pair 43, the cooling fan 49, the upper partition 45, and the rear partition 47 form a radiator unit 50. The refrigeration device 11 of this embodiment has two (a plurality of) radiator units 50.

[0031] When the cooling fan 49 is driven, cooling air is taken into the duct 46 from the front opening of the duct 46, and the air comes into contact with the unit intercooler 13a and the unit gas cooler 15a, thereby exchanging heat between the unit intercooler 13a and the unit gas cooler 15a. In addition, the air after heat exchange is discharged to the rear of the cooling fan 49 through each exhaust port 48. As shown in FIG. 1, the two radiator units 50 are installed on the left and right sides of the front of the machine compartment 21, and the compressor unit 28 is installed behind the radiator unit 50 on the right side. The compressor unit 28 is cooled by the air flow discharged rearward from the cooling fan 49 after cooling the right heat exchanger pair 43.

[0032] The high-pressure refrigerant that has dissipated heat in the gas cooler 15 further dissipates heat in the auxiliary heat exchanger 52 and the self heat exchanger 53 while reaching the expansion structure 16. Specifically, as shown in Fig. 3, the auxiliary heat exchanger 52 is composed of an auxiliary expander 55 provided in a branch pipe 54 branched from the refrigerant pipe 18 between the gas cooler 15 and the expansion structure 16, a heat absorption section 56 through which the refrigerant decompressed in the auxiliary expander 55 passes, and a heat dissipation section 57 provided in the refrigerant pipe 18 between the gas cooler 15 and the branched portion of the branch pipe 54, paired with the heat absorption section 56 to constitute a heat exchanger. In the branch pipe 54, the high-pressure refrigerant is decompressed in the auxiliary expander 55 to become an intermediate-pressure refrigerant, and the intermediate-pressure refrigerant exchanges heat with the heat dissipation section 57 in the heat absorption section 56, and then flows into the downstream side of the intercooler 13 and returns to the rear-stage compressor 14.

[0033] The self-heat exchanger 53 is configured by piping a part of the refrigerant piping 18 between the branched portion of the branch piping 54 and the expansion structure 16, and a part of the refrigerant piping 18 between the evaporator 17 and the front-stage compressor 12 in close contact with each other. In the self-heat exchanger 53, heat is exchanged between the high-pressure refrigerant flowing toward the expansion structure 16 and the low-pressure refrigerant flowing toward the front-stage compressor 12.

[0034] As described above, in the refrigeration apparatus 11 of the present embodiment, the intercooler 13 is configured with the two unit intercoolers 13a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18, so that the temperatures of the intermediate-pressure refrigerant that passes through each unit intercooler 13a and then joins can be made substantially equal to each other, and refrigerant flow turbulence that occurs when intermediate-pressure refrigerants with different temperatures join can be prevented, allowing the refrigerant to circulate smoothly. Similarly, the gas cooler 15 is configured with the two unit gas coolers 15a having the same heat radiation amount and connected in parallel to the refrigerant pipe 18, so that the temperatures of the high-pressure refrigerant that passes through each unit gas cooler 15a and then joins can be made substantially equal to each other, and refrigerant flow turbulence that occurs when high-pressure refrigerants with different temperatures join can be prevented, allowing the refrigerant to circulate smoothly. As described above, according to the refrigeration device 11 of the present embodiment, although the intercooler 13 and the gas cooler 15 are each composed of two (a plurality of) unit intercoolers 13a and unit gas coolers 15a, respectively, it is possible to prevent any adverse effects from occurring in the circulation of the refrigerant.

[0035] In addition, in the refrigeration device 11 of the present embodiment, the total amount of heat radiation of the economizer 13 can be adjusted by changing the number of unit economizers 13a, and the total amount of heat radiation of the gas cooler 15 can be adjusted by changing the number of unit gas coolers 15a, so that the total amount of heat radiation of the economizer 13 and the gas cooler 15 can be adjusted more easily. In addition, there is no need to prepare a plurality of types of unit radiators with different refrigeration capacities. It is also possible to quantitatively increase or decrease the total amount of heat radiation of the economizer 13 and the gas cooler 15 by preparing one type of unit economizer 13a and unit gas cooler 15a and simply changing the number of units. As described above, according to the present embodiment, it is possible to obtain a refrigeration device 11 having excellent versatility in which the total amount of heat radiation of the radiators can be easily adjusted to a heat radiation amount suitable for a required refrigeration capacity.

[0036] The system includes two radiator units 50 each including a heat exchanger pair 43 formed by arranging one unit intercooler 13a and one unit gas cooler 15a adjacent to each other in the front-rear direction, and a cooling fan 49 that supplies a cooling air flow to the heat exchanger pair 43, and the unit intercooler 13a is disposed upstream of the air flow and the unit gas cooler 15a is disposed downstream of the air flow in each heat exchanger pair 43. This allows the cooling air to exchange heat with the unit intercooler 13a in which an intermediate-pressure refrigerant having a relatively low refrigerant temperature circulates, and then exchange heat with the unit gas cooler 15a in which a high-pressure refrigerant having a relatively high refrigerant temperature circulates. This makes it possible to increase the temperature difference between the cooling air before heat exchange and the unit intercooler 13a, and the temperature difference between the cooling air whose temperature has increased by heat exchange with the unit intercooler 13a and the unit gas cooler 15a, respectively, and therefore improves the heat exchange efficiency in the intercooler 13a and the gas cooler 15a. Conversely, when the unit gas cooler 15a is arranged upstream of the cooling air flow and the unit intercooler 13a is arranged downstream of the cooling air flow, the temperature difference between the cooling air whose temperature has increased through heat exchange in the unit gas cooler 15a and the unit intercooler 13a becomes small, and a decrease in the heat exchange efficiency of the unit intercooler 13a located downstream is unavoidable.

[0037] Since the unit intercooler 13a and the unit gas cooler 15a are configured as a fin-tube type heat exchanger 34 including a group of fins 35 made of thin plates arranged in parallel in the left-right direction and a heat radiation pipe 36 that is repeatedly reversed in a serpentine shape and penetrates the group of fins 35 in the thickness direction, and the heat radiation pipe 36 is formed from a single seamless pipe material, it is possible to reduce the risk of refrigerant leakage and improve the reliability of the refrigeration device 11 compared to a configuration in which a joint portion joined by welding is formed on the heat radiation pipe 36. Such a configuration is particularly suitable for a refrigeration device 11 that uses a refrigerant with high operating pressure, for example, a refrigeration device 11 that uses carbon dioxide as a refrigerant.

[0038] Since the adjacent pitch P1 of the fins 35 of the unit intercooler 13a and the adjacent pitch P2 of the fins 35 of the unit gas cooler 15a are set to the same pitch, it is possible to make the ventilation resistance of the cooling air uniform over the entire left-right direction, and it is possible to prevent a decrease in heat exchange efficiency due to a partial increase in ventilation resistance. Furthermore, since the unit intercooler 13a and the unit gas cooler 15a are disposed adjacent to each other in the front-rear direction so that the fins 35 of the unit intercooler 13a and the fins 35 of the unit gas cooler 15a overlap when the heat exchanger pair 43 is viewed from the front, the cooling air that has passed between the fins 35 of the unit intercooler 13a can be made to flow smoothly between the fins 35 of the unit gas cooler 15a, and it is possible to prevent a decrease in the heat exchange efficiency between the fins 35 and the cooling air due to an eddy or the like being generated in the intake air flow for cooling.

[0039] In the above embodiment, carbon dioxide is used as the refrigerant of the refrigeration device 11, but the refrigerant is not limited to carbon dioxide. The unit intercooler 13a and the unit gas cooler 15a can be configured with a microchannel heat exchanger. The present invention can be applied to devices other than refrigerators. [Explanation of symbols]

[0040] 11 Refrigeration equipment 12 Pre-compressor 13 Pre-stage heat sink (intercooler) 13a Unit front stage radiator (unit intercooler) 14 Rear compressor 15 Post-heater (gas cooler) 15a Unit post-heater (unit gas cooler) 17 Evaporator 18 Refrigerant piping 34 Heat exchanger 35 Finn 36 Heat dissipation tube 43 Heat sink pair (heat exchanger pair) 49 Cooling Fan 50 Heat sink unit P1: Fin pitch of unit front-stage radiator P2: Adjacent pitch of fins of unit rear heat sink

Claims

1. a front-stage compressor (12) that compresses and discharges a low-pressure refrigerant evaporated in an evaporator (17); a front-stage radiator (13) that radiates heat from an intermediate-pressure refrigerant discharged from a front-stage compressor (12); a rear stage compressor (14) that compresses and discharges an intermediate pressure refrigerant whose heat has been radiated in a front stage radiator (13); a rear-stage radiator (15) for radiating heat from a high-pressure refrigerant discharged from a rear-stage compressor (14); a refrigerant pipe (18) to which the front-stage compressor (12), the front-stage radiator (13), the rear-stage compressor (14), and the rear-stage radiator (15) are connected; Equipped with The front-stage radiator (13) is composed of a plurality of unit front-stage radiators (13a, 13a) having the same heat radiation amount and connected in parallel to the refrigerant pipe (18), and the rear-stage radiator (15) is composed of a plurality of unit rear-stage radiators (15a, 15a) having the same heat radiation amount and connected in parallel to the refrigerant pipe (18), This refrigeration device is characterized in that it is configured so that the total amount of heat dissipation of the front-stage radiator (13) can be adjusted by changing the number of unit front-stage radiators (13a), and the total amount of heat dissipation of the rear-stage radiator (15) can be adjusted by changing the number of unit rear-stage radiators (15a).

2. The cooling system includes a plurality of radiator units (50) each including a radiator pair (43) formed by arranging one front-stage radiator unit (13a) and one rear-stage radiator unit (15a) adjacent to each other in the front-rear direction, and a cooling fan (49) for supplying a cooling air flow to the radiator pair (43), 2. The refrigeration system according to claim 1, wherein in each radiator pair (43), the unit front-stage radiator (13a) is arranged on the upstream side of the air flow, and the unit rear-stage radiator (15a) is arranged on the downstream side of the air flow.

3. The unit front-stage radiator (13a) and the unit rear-stage radiator (15a) are each composed of a fin-tube type heat exchanger (34) including a group of fins (35) made of thin plates arranged in parallel in the left-right direction, and a heat dissipation tube (36) that is repeatedly inverted in a serpentine shape and penetrates the group of fins (35) in the thickness direction, 3. The refrigeration system according to claim 2, wherein the heat radiation pipe (36) is formed from a single seamless pipe material.

4. The group of fins (35) of the unit front-stage radiator (13a) and the group of fins (35) of the unit rear-stage radiator (15a) are respectively arranged at equal intervals, The adjacent pitch (P1) of the fins (35) of the unit front-stage radiator (13a) and the adjacent pitch (P2) of the fins (35) of the unit rear-stage radiator (15a) are set to the same pitch, 4. A refrigeration apparatus as described in claim 3, wherein the unit front-stage radiator (13a) and the unit rear-stage radiator (15a) are arranged adjacent to each other in the front-to-rear direction so that, when the radiator pair (43) is viewed from the front, the fins (35) of the unit front-stage radiator (13a) and the fins (35) of the unit rear-stage radiator (15a) overlap.

Images