Unit cooler

Abstract

We provide a unit cooler that reduces costs and saves energy while suppressing the generation of haze and performing efficient defrosting. [Solution] The unit cooler has a heat exchanger equipped with fins, cooling pipes inserted through cooling pipe holes in the fins, and defrost pipes inserted through defrost pipe holes in the fins. The defrost pipes are connectable to a hot brine supply source, and the number of defrost pipes per unit area in the lower region of the heat exchanger is greater than the number of defrost pipes per unit area in the upper region above the lower region of the heat exchanger. This provides a unit cooler that can efficiently defrost while suppressing the generation of haze, thereby reducing costs and saving energy.

Description

Technical Field

[0001] The present invention relates to a unit cooler.

Background Art

[0002] A unit cooler that supplies cold air to a large refrigerator, freezer, etc. is configured to cool the air taken in from outside the housing through a heat exchanger inside the housing and supply the cold air into the refrigerator or freezer. In such a unit cooler, when the moisture contained in the air is cooled, it may adhere to the surfaces such as the fins of the heat exchanger as frost, thereby causing a decrease in the cooling capacity of the heat exchanger.

[0003] Therefore, in order to remove the frost adhering to the heat exchanger, defrosting is generally performed in the unit cooler. As defrosting, a hot gas defrosting method using hot gas to melt the frost adhering to the heat exchanger, a heater defrosting method using a heated heater to melt the frost, etc. are known. Patent Document 1 discloses a unit cooler that performs hot gas defrosting.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the heater defrosting method, a heater placed inside the heat exchanger is heated to around 200°C to melt the frost, which tends to generate haze, and also requires a large amount of electricity to power the heater, making it inefficient. On the other hand, the hot gas defrosting method supplies high-pressure refrigerant into the heat exchanger through piping, requiring less electricity than the heater defrosting method, but the hot gas defrosting method also suffers from the problem of haze generation.

[0006] Therefore, the present invention aims to provide a unit cooler that can suppress the generation of haze and perform defrosting efficiently. [Means for solving the problem]

[0007] To achieve the above objective, the unit cooler of the present invention is The heat exchanger comprises fins, cooling pipes inserted through cooling pipe holes in the fins, and defrost pipes inserted through defrost pipe holes in the fins. The defrosting piping can be connected to a hot brine supply source. The number of defrosting pipes per unit area in the lower region of the heat exchanger is greater than the number of defrosting pipes per unit area in the upper region above the lower region of the heat exchanger. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a unit cooler that can efficiently defrost while suppressing the generation of haze, thereby reducing costs and saving energy. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic front view showing a unit cooler according to an embodiment of the present invention. [Figure 2] Figure 2 is a side view of the AA cross-section of the unit cooler shown in Figure 1. [Figure 3]Figure 3 is a side view of the heat exchanger. [Figure 4] Figure 4 is a schematic diagram showing the hot brine supply system. [Modes for carrying out the invention]

[0010] In this specification, "up" and "down" mean the direction of gravity acceleration (upwards or in the anti-gravity direction) and the direction of gravity acceleration (downwards or in the direction of gravity), respectively. Furthermore, the drawings show a general overview of each part and may not represent actual dimensions or proportions.

[0011] Figure 1 is a schematic front view of a unit cooler 10 according to an embodiment of the present invention. Figure 2 is a side view of the AA cross-section of the unit cooler 10 in Figure 1.

[0012] In the figure, the unit cooler 10 comprises a housing 12 with a roughly rectangular parallelepiped-shaped space inside, a heat exchanger 20 located inside the housing 12, a pair of duct fan modules 30 mounted on the front of the housing 12, and a drain device 40 located at the bottom of the housing 12. The rear of the housing 12 (right side in Figure 2) is open to allow air to be drawn in from the outside into the housing 12 when the duct fan modules 30 are operating.

[0013] In the heat exchanger 20, refrigerant piping (not shown) is arranged in multiple bends, allowing refrigerant supplied from the outside to pass through the refrigerant piping. In addition, defrosting piping (details will be described later) is arranged to pass between the refrigerant piping.

[0014] The unit cooler 10 of this embodiment is installed on the floor of a large refrigerator or freezer (not shown) via a drain device 40. However, the unit cooler 10 may be suspended from the ceiling of the refrigerator or freezer using appropriate means (for example, a wire connected to the ceiling surface of the housing 12).

[0015] The drain device 40 has, in this order from below, a base 41 installed on the floor surface, a drain pan 42, a trace tube unit 43, and a heat dissipation plate 44.

[0016] The base 41 has a pair of legs 41a and 41b corresponding to the front side and the back side of the housing 12, a bottom plate 41c, and a heat insulating material 41f.

[0017] A rectangular plate-shaped heat insulating material 41f is disposed in a space surrounded by the legs 41a and 41b and the bottom plate 41c so as to be placed on the bottom plate 41c. The heat insulating material 41f preferably has a uniform thickness of, for example, 10 mm and is formed of a foamed material such as urethane, but the material is not limited.

[0018] The drain pan 42 is formed by bending. The trace tube unit 43 has an upstream box 43a in the shape of a hollow rectangular parallelepiped, a downstream box 43b in the shape of a hollow rectangular parallelepiped, and a plurality (here, three) of pipe lines 43c having a rectangular tube-shaped outer peripheral surface connecting the upstream box 43a and the downstream box 43b.

[0019] One end of an inlet-side pipe 43m disposed on the upper surface thereof is connected to the upstream box 43a. The other end of the inlet-side pipe 43m is connected to a supply pipe for a hot line (antifreeze), not shown, and the hot line can be supplied from the supply pipe to the upstream box 43a through the inlet-side pipe 43m.

[0020] One end of an outlet-side pipe 43n disposed on the upper surface thereof is connected to the downstream box 43b. The other end of the outlet-side pipe 43n is connected to a discharge pipe for the hot line, and the hot line can be discharged from the downstream box 43b through the outlet-side pipe 43n to the discharge pipe.

[0021] Each pipe line 43c is attached to the heat dissipation plate 44. The upper surfaces of the upstream box 43a and the downstream box 43b and the upper surface of the pipe line 43c also adhere to the lower surface of the heat dissipation plate 44.

[0022] Figure 3 is a side view of the heat exchanger 20, but the cooling piping is omitted. The heat exchanger 20 is formed by combining five vertically elongated coil units CU horizontally. Each coil unit CU has a common configuration. Each coil unit CU has a number of parallel-arranged thin metal fins 21, cooling piping (not shown), and defrosting piping 22 (see Figure 4). However, a heat exchanger consisting of a single coil unit may be used by using large-area fins.

[0023] Each fin 21 has a common shape and includes cooling pipe holes 21a and 21b arranged in two horizontal rows and aligned vertically, and defrosting pipe holes 21c arranged in a single row along the vertical direction between the rows of cooling pipe holes 21a and 21b.

[0024] Furthermore, defrosting pipe holes 21d and 21e are formed aligned below the lowest cooling pipe holes 21a and 21b. The distance between the centers of the lowest cooling pipe holes 21a and 21b and the defrosting pipe holes 21d and 21e is equal to the pitch p of the cooling pipe holes 21a and 21b. Here, the defrosting pipe holes 21d and 21e are referred to as the lowest defrosting pipe holes, and the defrosting pipes 22 inserted through the defrosting pipe holes 21d and 21e are referred to as the lowest defrosting pipes.

[0025] However, instead of providing defrosting pipe holes 21d and 21e, the defrosting pipes 22 may be inserted through the lowest cooling pipe holes 21a and 21b in each row. In this case, drilling the fins 21 becomes easier. In this case, the lowest cooling pipe holes 21a and 21b in each row are called the lowest defrosting pipe holes, and the defrosting pipes 22 inserted through them are called the lowest defrosting pipes.

[0026] Cooling pipes (not shown) are inserted through the cooling pipe holes 21a and 21b, and a defrost pipe 22 is inserted through the selected defrost pipe hole 21c. The inner diameter of the defrost pipe hole 21c is larger than the inner diameters of the cooling pipe holes 21a and 21b, and may vary depending on the inner diameters of the cooling pipe holes 21a and 21b.

[0027] The cooling pipe holes 21a are arranged at equal intervals in the vertical direction with a constant pitch p, and the cooling pipe holes 21b are also arranged at equal intervals in the vertical direction with a constant pitch p. By forming the cooling pipe holes 21a and 21b and the defrost pipe hole 21c in the vertical direction with a constant pitch, the machinability can be improved.

[0028] The horizontal distance between the centers of the cooling pipe holes 21a and 21b is d. However, the cooling pipe hole 21b is shifted vertically relative to the cooling pipe hole 21a by a shift amount s1. Preferably, s1 = p / 2.

[0029] The defrosting pipe holes 21c are also arranged at equal intervals in the vertical direction with a constant pitch p, but they are positioned between the cooling pipe holes 21a and 21b in the horizontal and vertical directions. Specifically, they are shifted vertically by a shift amount s2 and horizontally by a shift amount s3 relative to the cooling pipe holes 21a. Here, the defrosting pipe holes 21c are formed between horizontally adjacent cooling pipe holes 21a and 21b (at a position that coincides with the line segment connecting the centers of the cooling pipe holes 21a and 21b).

[0030] The defrosting pipe 22 passing through the fin 21 is a straight pipe, and its end is connected to the end of another defrosting pipe 22 by a U-shaped bent pipe. In this embodiment, the ends of the defrosting pipes 22 are connected by three types of U-shaped pipes 23, 24, and 25. Alternatively, a so-called hairpin pipe can be used, which is formed by bending a long straight pipe in the middle to create two straight pipe sections and a U-shaped bent pipe section that connects the ends of the straight pipe sections. In the case of a hairpin pipe, for convenience, the straight pipe section will be referred to as the defrosting pipe, and the U-shaped bent pipe section will be referred to as the U-shaped pipe.

[0031] More specifically, one U-shaped pipe 23 is provided at one end of a single coil unit CU (the side shown in Figure 3), and connects the ends of the defrost pipes 22 that are inserted through the lowest defrost pipe holes 21d and 21e. For this reason, the U-shaped pipe 23 is inclined with respect to the vertical direction. On the other end of the heat exchanger 20, as shown by the dotted line, the end of the defrost pipe 22 inserted through the defrost pipe hole 21e is connected by the U-shaped pipe 23 to the end of the defrost pipe 22 inserted through the lowest defrost pipe hole 21c.

[0032] For example, two U-shaped pipes 24 are provided at one end of a single coil unit CU, connecting the ends of defrosting pipes 22 that are inserted through vertically adjacent defrosting pipe holes 21c. Therefore, the U-shaped pipes 24 extend in the vertical direction. At the other end of the heat exchanger 20, as shown by the dotted line, the ends of defrosting pipes 22 inserted through defrosting pipe holes 21c are connected by similar U-shaped pipes 24 to the ends of vertically adjacent defrosting pipes 22.

[0033] For example, five U-shaped pipes 25 are provided at one end of a single coil unit CU, connecting the ends of defrost pipes 22 inserted into the (N+1)th and (N+4)th holes (selected holes) of the vertically arranged defrost pipe holes 21c. Defrost pipes 22 are not inserted into the (N+2)th and (N+3)th holes (unselected holes) of the defrost pipe holes 21c. Therefore, the U-shaped pipes 25 extend vertically and are longer than the U-shaped pipes 24. At the other end of the heat exchanger 20, as shown by the dotted line, the ends of defrost pipes 22 inserted into the defrost pipe holes 21c are connected by similar U-shaped pipes 24 to the ends of defrost pipes 22 arranged vertically adjacent to each other. Note that defrost pipes 22 are not inserted into the uppermost hole of the defrost pipe holes 21c.

[0034] As is clear from the above, in each coil unit CU, the lowest defrost pipe 22 is connected in series to the uppermost defrost pipe 22 via U-shaped pipes 23, 24, 25 and other defrost pipes 22, and hot brine flows through this path.

[0035] Here, the region of the heat exchanger 20 where the U-shaped pipe 23 is installed is defined as the lower region LR, the region of the heat exchanger 20 where the U-shaped pipe 24 is installed is defined as the intermediate region CR, and the region of the heat exchanger 20 where the U-shaped pipe 25 is installed is defined as the upper region UR. However, the intermediate region CR may also be included in the lower or upper region. Here, the number of defrosting pipes 22 per unit area is highest in the lower region LR, followed by the intermediate region CR, and the number of defrosting pipes 22 per unit area is lowest in the upper region UR. In other words, the density of defrosting pipes 22 per unit area (based on the area of ​​the fins 21) is highest in the lower region LR, lowest in the upper region UR, and intermediate region CR has a density between the two.

[0036] Furthermore, in the upper region UR, the amount of heat supplied during defrosting can be adjusted by selecting the defrosting pipe holes 21c and inserting the defrosting pipes 22 through them. More specifically, if the amount of heat for defrosting is insufficient in the upper region UR, for example, the number of defrosting pipes 22 per unit area can be increased by inserting the defrosting pipes 22 through the (N+1)th and (N+3)th holes of the defrosting pipe holes 21c, thereby increasing the amount of heat supplied to the upper region UR. On the other hand, if there is excessive defrosting in the upper region UR, for example, the number of defrosting pipes 22 per unit area can be decreased by inserting the defrosting pipes 22 through the (N+1)th and (N+5)th holes of the defrosting pipe holes 21c, thereby decreasing the amount of heat supplied to the upper region UR. In such cases, the ends of the defrosting pipes 22 are connected by U-shaped pipes of a different length than the U-shaped pipe 25. In the intermediate CR region, the amount of heat supplied during defrosting can be adjusted in a similar manner.

[0037] Figure 4 is a schematic diagram showing the hot brine supply system, but the U-tube and defroster are shown schematically. In Figure 4, heated hot brine can be supplied from the hot brine supply source HS to the unit cooler 10 via the supply side piping SP. The supply side piping SP is connected to, for example, a distribution section (not shown), and the hot brine that reaches the distribution section is distributed to the lowest defrosting piping 22 via five branch pipes.

[0038] On the other hand, the defrosting pipe 22 at the top of each coil unit is connected to a manifold (not shown), and the hot brine that merges at the manifold is collected back to the supply source HS via the discharge pipe EP and reused. Alternatively, hot brine may be supplied from the supply source HS to the trace pipe unit 43 (see Figure 1).

[0039] (Operation of the unit cooler) Next, the operation of the unit cooler 10 will be described. In Figure 1, during the cooling operation of the unit cooler 10, the fins 21 are cooled by flowing cooled refrigerant through the cooling pipes. From this state, when the fan of the duct fan module 30 is driven to rotate, air drawn in from the opening on the back of the unit cooler 10 is cooled as it passes between the fins 21 of the heat exchanger 20, and is discharged to the outside of the unit cooler 10 through the opening on the front (the duct of the duct fan module 30 in this embodiment), cooling the outside space.

[0040] (Defrost operation) The defrost operation will now be described. The defrost operation can be performed by switching the unit cooler 10 to the defrost operation mode. In the defrost operation mode, hot brine heated to 15-25°C in the supply source HS is supplied to the heat exchanger 20 via the supply side piping SP. Specifically, the relatively high-temperature hot brine that enters the defrost piping 22 in the lower region LR via the supply side piping SP heats the surrounding fins 21 and cooling pipes, melting the frost that has accumulated on them.

[0041] After passing through the defrosting pipe 22 in the lower region LR, the hot brine, whose temperature has decreased, then enters the defrosting pipe 22 in the intermediate region CR, heating the surrounding fins 21 and cooling pipes and melting the frost that has accumulated on them. Furthermore, after passing through the defrosting pipe 22 in the intermediate region CR, the hot brine, whose temperature has decreased, then enters the defrosting pipe 22 in the upper region UR, heating the surrounding fins 21 and cooling pipes and melting the frost that has accumulated on them, before returning to the supply source HS through the discharge pipe EP.

[0042] Generally, the water cooled within the heat exchanger 20 descends and adheres to the fins 21 and cooling pipes as frost. Therefore, the amount of frost that adheres per unit area increases in the upper region UR, the middle region CR, and the lower region LR, in that order.

[0043] According to this embodiment, by first supplying relatively high-temperature hot brine from the supply source HS to the lower region LR where the largest amount of frost accumulates, the frost can be efficiently melted. Furthermore, since the heat from the defrosting pipes 22 in the lower region LR is transferred upward by convection and heat transfer and reaches the intermediate region CR, the intermediate region CR can utilize the heat from the defrosting pipes 22 in the lower region LR, in addition to the heat released by the defrosting pipes 22 in the intermediate region CR, for defrosting, thereby effectively melting the frost. Moreover, since the heat from the lower region LR and the intermediate region CR is transferred upward by convection and heat transfer and reaches the upper region UR, the upper region UR can be defrosted even with an even lower density of defrosting pipes 22.

[0044] In the lower region LR, the defrost pipes 22 are located in the defrost pipe holes 21d and 21e (the lowest defrost pipe holes). Therefore, unlike the intermediate region CR and the upper region UR, the defrost pipes 22 are located directly below the cooling pipes. As a result, the heat from the defrost pipes 22 in the lower region LR that is not used for defrosting in the lower region LR is effectively transferred to the defrost pipes 22 in the intermediate region CR, which are located directly above, through convection and heat transfer.

[0045] In addition, since the number of defrosting pipes 22 installed per unit area in the lower region LR is greater than the number of defrosting pipes 22 installed per unit area in the intermediate region CR, even if the amount of frost that accumulates in the lower region LR is greater than the amount of frost that accumulates in the intermediate region CR, the frost can be melted in a short time.

[0046] Furthermore, since the number of defrosting pipes 22 installed per unit area in the intermediate region CR is greater than the number of defrosting pipes 22 installed per unit area in the upper region UR, even if the amount of frost accumulating in the intermediate region CR is greater than the amount of frost accumulating in the upper region UR, the frost can be melted in a short time. This allows the frost melting times in the lower region LR, the intermediate region CR, and the upper region UR to be synchronized, contributing to a reduction in the overall defrosting time of the heat exchanger 20.

[0047] According to this embodiment, defrosting can be performed efficiently without increasing the temperature of the hot brine supplied from the supply source HS. This reduces the equipment cost of the hot brine supply system and saves energy by reducing the power required to heat the hot brine. Furthermore, by keeping the temperature of the hot brine passing through the defrosting pipe 22 low, it is also possible to suppress the generation of haze.

[0048] The melted water from the frost in each section falls onto the heat diffusion plate 44 before it falls from the heat exchanger 20 into the drain pan 42. In this embodiment, the heat diffusion plate 44 is heated by the hot brine passing through the trace tube unit 43, which suppresses the freezing of the melted water on the heat diffusion plate 44.

[0049] The molten water that falls onto the heat diffusion plate 44 flows downstream along its slope without freezing and is discharged to the outside through the drain pipe 42k provided in the drain device 40.

[0050] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made.

[0051] This specification includes disclosures of the following inventions. (First aspect) The heat exchanger comprises fins, cooling pipes inserted through cooling pipe holes in the fins, and defrost pipes inserted through defrost pipe holes in the fins. The defrosting piping can be connected to a hot brine supply source. The number of defrost pipes per unit area in the lower region of the heat exchanger is greater than the number of defrost pipes per unit area in the upper region above the lower region of the heat exchanger. A unit cooler characterized by the following features.

[0052] (Second aspect) When hot brine is supplied from the aforementioned source, it passes through the defrosting pipe in the lower region, and then through the defrosting pipe in the upper region. A unit cooler according to a first embodiment, characterized by the following:

[0053] (Third aspect) The number of defrost pipes per unit area in the lower region of the heat exchanger is greater than the number of defrost pipes per unit area in the intermediate region that is below the upper region and above the lower region. A unit cooler according to a first embodiment, characterized by the following:

[0054] (Fourth aspect) When hot brine is supplied from the aforementioned supply source, it passes through the defrosting pipe in the lower region, then through the defrosting pipe in the intermediate region, and further through the defrosting pipe in the upper region. A third embodiment of a unit cooler characterized by the following:

[0055] (Fifth aspect) The length of the U-shaped pipe connecting the ends of the defrosting pipes arranged vertically in the upper region is longer than the length of the U-shaped pipe connecting the ends of the defrosting pipes arranged vertically in the intermediate region. A unit cooler according to the third or fourth embodiment, characterized by the above.

[0056] (Sixth aspect) In each fin, the cooling pipe holes are arranged horizontally and aligned at equal pitches vertically. Between the rows of cooling pipe holes, the defrosting pipe holes are aligned at equal pitches in the vertical direction. One of the horizontally adjacent cooling pipe holes is shifted vertically relative to the other. The defrosting pipe holes are formed between the horizontally adjacent cooling pipe holes. A unit cooler according to any of the first to fifth embodiments, characterized by the above.

[0057] (Seventh aspect) In the upper region, the defrost pipe is inserted through the selected defrost pipe hole, and the defrost pipe is not inserted through the defrost pipe hole that is not selected. A unit cooler according to a sixth embodiment, characterized by the following:

[0058] (Eighth aspect) In the lower region, below the lowest of the two rows of cooling pipe holes, the lowest defrost pipe hole is formed. The lowest defrost pipe is inserted through the lowest defrost pipe hole. A unit cooler according to the sixth or seventh embodiment, characterized by the above.

[0059] (Ninth aspect) In the lower region, the lowest defrost pipe is inserted through the lowest of the two rows of cooling pipe holes. A unit cooler according to the sixth or seventh embodiment, characterized by the above. [Explanation of symbols]

[0060] 10 Unit Cooler 12 cabinets 20 Heat exchanger 30 Duct Fan Modules 21 fins 21a, 21b Cooling piping holes 21c, 21d, 21e Defrost pipe holes 22 Defrosting pipes 23,24,25 U-shaped tube 40 Drain device 41 Base 41a Front leg 41b Rear leg section 41c bottom plate 41f insulation 42 Drain pan 43 Trace tube unit 44 Heat Diffuser CU Coil Unit LR lower area CR intermediate area UR upper area HS Hot Brine Supply Source

Claims

1. The heat exchanger comprises fins, cooling pipes inserted through cooling pipe holes in the fins, and defrost pipes inserted through defrost pipe holes in the fins. The defrosting piping can be connected to a hot brine supply source. The number of defrost pipes per unit area in the lower region of the heat exchanger is greater than the number of defrost pipes per unit area in the upper region above the lower region of the heat exchanger. A unit cooler characterized by the following features.

2. When hot brine is supplied from the aforementioned source, it passes through the defrosting pipe in the lower region, and then through the defrosting pipe in the upper region. The unit cooler according to feature 1.

3. The number of defrost pipes per unit area in the lower region of the heat exchanger is greater than the number of defrost pipes per unit area in the intermediate region that is below the upper region and above the lower region. The unit cooler according to feature 1.

4. When hot brine is supplied from the aforementioned supply source, it passes through the defrosting pipe in the lower region, then through the defrosting pipe in the intermediate region, and further through the defrosting pipe in the upper region. The unit cooler according to feature 3.

5. The length of the U-shaped pipe connecting the ends of the defrosting pipes arranged vertically in the upper region is longer than the length of the U-shaped pipe connecting the ends of the defrosting pipes arranged vertically in the intermediate region. The unit cooler according to feature 3.

6. In each fin, the cooling pipe holes are arranged horizontally and aligned at equal pitches vertically. Between the rows of cooling pipe holes, the defrosting pipe holes are aligned at equal pitches in the vertical direction. One of the horizontally adjacent cooling pipe holes is shifted vertically relative to the other. The defrosting pipe holes are formed between the horizontally adjacent cooling pipe holes. The unit cooler according to feature 1.

7. In the upper region, the defrost pipe is inserted through the selected defrost pipe hole, and the defrost pipe is not inserted through the defrost pipe hole that is not selected. The unit cooler according to feature 6.

8. In the lower region, below the lowest of the two rows of cooling pipe holes, a lowermost defrost pipe hole is formed. The lowest defrost pipe is inserted through the lowest defrost pipe hole. The unit cooler according to feature 6.

9. In the lower region, the lowest defrost pipe is inserted through the lowest of the two rows of cooling pipe holes. The unit cooler according to feature 6.

Images