Unit cooler

Abstract

To provide a unit cooler which can efficiently perform defrosting using a hot gas while inhibiting occurrence of mist.SOLUTION: A unit cooler includes: a housing through which air passes; a fan device including a fan for introducing air into the housing; and a heat exchanger disposed in the housing. The heat exchanger has: a plurality of fins; a cooling pipe penetrating through the fins; and a defrost pipe penetrating through the fins. The cooling pipe is supplied with a refrigerant cooled to a temperature lower than a normal temperature, and the defrost pipe is supplied with the refrigerant heated to a temperature higher than the normal temperature. A density of the defrost pipe penetrating through a first area of the fins is higher than a density of the defrost pipe penetrating through a second area located higher than the first area of the fins.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A unit cooler that supplies cold air to a large refrigerator, freezer, or the like is configured to take in outside air from outside the housing, cool it through a heat exchanger inside the housing, and supply the cold air to the refrigerator or freezer. In such a unit cooler, when the moisture in the outside air is cooled, it can form frost on the surfaces of the heat exchanger fins, etc., which reduces the cooling capacity of the heat exchanger.

[0003] Therefore, defrosting is generally performed in unit coolers to remove frost that has adhered to the heat exchanger. A known defrosting method is a hot gas defrosting method that uses hot gas to melt the frost that has adhered to the heat exchanger. Patent Document 1 discloses a unit cooler that performs hot gas defrosting. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 05-059167 Summary of the Invention [Problem to be solved by the invention]

[0005] In the unit cooler of Patent Document 1, a dedicated hot gas circuit is installed on the air intake side of the heat exchanger, and a dedicated hot gas circuit is also installed in the drain pan that receives drain water that melts from the cooling pipe surface of the cooler during defrosting, so that hot gas is supplied to these dedicated hot gas circuits during defrosting.

[0006] However, frost or ice may also adhere to the air discharge side of the heat exchanger, and the unit cooler of Patent Document 1 does not provide sufficient measures to prevent this.

[0007] Furthermore, in recent years, global warming has been recognized as a global problem, and as one solution to this problem, the use of CO2 instead of the fluorocarbon-based refrigerants currently used in refrigeration cycles is being considered.If defrosting is performed using CO2 as hot gas in the unit cooler of Patent Document 1, there is a risk of mist being generated inside the unit cooler if high-temperature, high-pressure CO2 is flowed into a circuit dedicated to hot gas.

[0008] The present invention has been made in view of the above-mentioned problems, and has an object to provide a unit cooler that can efficiently perform defrosting using hot gas while suppressing the generation of mist. [Means for solving the problem]

[0009] In order to achieve the above object, the unit cooler according to the present invention comprises: a housing through which air passes; a fan device including a fan that introduces air into the housing; a heat exchanger disposed within the housing; The heat exchanger has a plurality of fins, a cooling pipe passing through the fins, and a defrosting pipe passing through the fins, A refrigerant cooled below room temperature is supplied to the cooling pipe, and a refrigerant heated above room temperature is supplied to the defrosting pipe, The density of the defrosting pipes that penetrate the first region of the fin is higher than the density of the defrosting pipes that penetrate the second region of the fin above the first region. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a unit cooler that can efficiently perform defrosting using hot gas while suppressing the generation of mist. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a refrigeration cycle including a unit cooler according to this embodiment. [Figure 2] FIG. 2 is a front view of the unit cooler according to this embodiment. [Figure 3] FIG. 3 is a schematic diagram showing the unit cooler of FIG. 2 as viewed from the side in the direction of arrow A, with the defrosting piping seen through. [Figure 4] FIG. 4 is a front view of the unit cooler with the duct fan module and the front wall and top wall to which it is attached removed. [Figure 5] FIG. 5 is a schematic diagram showing a piping system for hot gas of the unit cooler. [Figure 6] FIG. 6 is a side view of the unit cooler taken along the line BB in FIG. [Figure 7] FIG. 7 is a side view of the unit cooler taken along the line CC in FIG. [Figure 8] FIG. 8 is an enlarged view of a part of the heat exchanger shown in FIG. [Figure 9] FIG. 9 is an enlarged view of a part of the heat exchanger shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a refrigeration cycle including a unit cooler 10 of this embodiment.

[0013] In FIG. 1, the gas cooler GC and on-off valve VL are connected by piping H1, the on-off valve VL and expansion valve EX are connected by piping H2, and the on-off valve VL and refrigerant inlet CI of the unit cooler 10 are connected by piping H3. The refrigerant outlet CO of the unit cooler 10 is connected to the accumulator ACC by piping H4, the accumulator ACC and compressor COMP by piping H5, and the compressor COMP and switching valve (three-way valve) EV by piping H6. The switching valve EV and hot gas inlet HI of the unit cooler 10 are connected by piping H7, and the switching valve EV and gas cooler GC are connected by piping H8. The hot gas outlet HO of the unit cooler 10 and compressor COMP are connected by piping H9. Refrigerant can pass through each of the piping.

[0014] (Operation of the refrigeration cycle) During cooling operation using the refrigeration cycle shown in Figure 1, the on-off valve VL is opened, and the switching valve EV connects the pipes H6 and H8 and blocks the pipe H7. When the compressor COMP is operated in this state, the compressed high-temperature, high-pressure refrigerant is pumped through the pipes H6 and H8 to the gas cooler GC, where it is cooled.

[0015] The cooled refrigerant passes through pipe H1 to on-off valve VL, then passes through expansion valve EX and enters the cooling pipe of the heat exchanger of unit cooler 10, where it expands, cooling the heat exchanger further below room temperature (here, the temperature inside the refrigerator) and lowering its pressure. This allows heat exchange with the air passing around the heat exchanger. After heat exchange, the refrigerant passes from unit cooler 10 through pipe H4 and enters accumulator ACC, where it is separated into gas and liquid, and the gas refrigerant returns to compressor COMP and is compressed again.

[0016] (Defrost operation) During defrosting, the on-off valve VL is closed, and the switching valve EV connects the pipes H6 and H7 and shuts off the pipe H8. When the compressor COMP is operated in this state, the compressed high-temperature, high-pressure refrigerant is heated above room temperature and sent as hot gas through the pipes H6 and H7 to the defrosting pipe of the unit cooler 10, where it heats the heat exchanger 20 and melts the frost and ice adhering to the fins, etc., thereby performing defrosting. After defrosting, the refrigerant returns to the compressor COMP through the pipe H9.

[0017] FIG. 2 is a front view of the unit cooler 10 according to this embodiment, with the drain pan shown in a see-through state. FIG. 3 is a schematic side view of the unit cooler 10 in FIG. 2, taken in the direction of arrow A, with the defrosting piping shown in a see-through state. In FIG. 3, the flow of hot gas is shown schematically by arrows. FIG. 4 is a front view of the unit cooler 10 with the duct fan module (fan device) 30 and the front wall and top wall to which it is attached removed. In this specification, "downward" refers to downward in the direction of gravity, and "upward" refers to upward in the direction of gravity.

[0018] 2 and 3, unit cooler 10 includes a housing 12 that defines a substantially rectangular parallelepiped space inside and has a drain pan 18 at the bottom, a heat exchanger 20 (also called a coil) disposed inside housing 12, and a pair of duct fan modules 30 attached to the front face (left side in FIG. 2) of housing 12. The back face (right side in FIG. 3) of housing 12 is open so that air can be taken in from the outside into housing 12 when duct fan module 30 is operating, and this opening is covered by a hood 13.

[0019] In this embodiment, the unit cooler 10 is installed on the floor of a large refrigerator, freezer, or the like (not shown) via legs, for example. However, the unit cooler 10 may be suspended from the ceiling of the refrigerator or freezer by connecting a hanging ring 14 fixed to the top surface of the housing 12 to the ceiling of the refrigerator or the like via an appropriate means (wire, etc.).

[0020] In FIG. 4, the heat exchanger 20 comprises a cooling pipe 21 through which a refrigerant passes, a hot gas pipe (defrosting pipe) 200 through which hot gas passes, and a number of rectangular thin plate-shaped fins 22 joined around these pipes and extending in parallel.

[0021] Fig. 5 is a schematic diagram showing the piping system for hot gas piping in the unit cooler 10. In Fig. 5, the flow of hot gas is indicated by arrows. Fig. 6 is a side view of the BB cross section in Fig. 4. Fig. 7 is a side view of the CC cross section in Fig. 4. Note that Figs. 6 and 7 show the cooling piping and hot gas piping only schematically and may differ from the actual piping.

[0022] 5, the hot gas piping 200 has a lower piping system (first piping system) 210 and an upper piping system (second piping system) 220. The lower piping system 210 has a hollow cylindrical lower distribution section 212 connected to a hot gas inlet pipe 211 that leads to a hot gas inlet HI (FIG. 2), a plurality of lower pipes 213 each having one end connected to the lower distribution section 212, and a hollow cylindrical lower collection section 214 to which the other ends of the lower pipes 213 are connected.

[0023] The axes of the lower distribution section 212 and the lower collection section 214 extend horizontally and are arranged to coincide with each other, and the lower pipes 213 each have a substantially U-shape and are arranged in contact with the inclined drain pan 18 (FIGS. 6 and 7). In FIG. 5, five lower pipes 213 are shown for ease of understanding, but in reality, a greater number of lower pipes 213 are provided.

[0024] The upper piping system 220 has a hollow cylindrical upper distribution section 222, a plurality of upper pipes 223, each connected at one end to the upper distribution section 222, and a hollow cylindrical upper collection section 224, to which the other ends of the upper pipes 223 are connected. The upper distribution section 222 is connected to the lower collection section 214 via a connecting pipe 230 extending vertically, and the upper collection section 224 is connected to the hot gas outlet HO (FIG. 2) via a hot gas outlet pipe 221.

[0025] The axes of the upper distribution section 222 and the upper collection section 224 extend vertically and are parallel to each other, and the upper distribution section 222 and the upper collection section 224 are preferably disposed near both ends of the fins 22 in the left-right direction in Fig. 6, for example. The upper piping 223, which is a piping for defrosting, passes through all of the fins 22 in the direction in which the fins 22 are arranged, exits the last fin 22 in the direction of arrangement, makes a U-turn to re-enter the same fin 22, passes through all of the fins 22 again in the direction of arrangement of the fins 22, and makes another U-turn, repeating this process multiple times, and has a bent shape.

[0026] One upper pipe 223 extends horizontally to the upper distribution section 222 and the upper collection section 224, and the other upper pipe 223 extends horizontally above it, but it may extend horizontally, then vertically, and then horizontally again. Upper pipes 223 having such a shape are arranged in multiple layers, stacked one on top of the other. In Figure 5, five upper pipes 223 are shown for ease of understanding, but in reality, a greater number of upper pipes 223 are provided.

[0027] During defrosting, hot gas injected from hot gas inlet pipe 211 passes through multiple lower pipes 213 from lower distribution section 212, and in the process, lower pipes 213 heat drain pan 18, melting frost and ice adhering to drain pan 18 and preventing frost and ice from adhering to drain pan 18. Thereafter, the hot gas is collected in lower collection section 214 and sent to upper distribution section 222 via connecting pipe 230.

[0028] The hot gas then passes from the upper distribution section 222 through the upper piping 223, and in the process heats the fins 22 and the surrounding area that the upper piping 223 comes into contact with, melting frost and ice that has adhered to the fins 22 and the cooling piping, etc. The hot gas is then collected in the upper collection section 224 and discharged through the hot gas outlet pipe 221.

[0029] Fig. 8 is an enlarged view of a portion of the heat exchanger shown in Fig. 6, and Fig. 9 is an enlarged view of a portion of the heat exchanger shown in Fig. 7. In Figs. 8 and 9, the upper piping 223 protruding from the farthest fin 22 in the arrangement direction and making a U-turn is shown by a dotted line, the upper piping 223 protruding from the foremost fin 22 and making a U-turn is shown by a solid line, and the flow of air passing through the heat exchanger 20 along the surface direction of the fins 22 is shown by arrow D.

[0030] 8 and 9, the cooling pipes 21 have straight pipe sections 21a that extend perpendicular to the fins 22 and are arranged in multiple rows and columns. After passing the last fin 22 in the direction in which the fins 22 are arranged, each straight pipe section 21a is connected to the adjacent straight pipe section 21a via a U-turn section. Here, a vertical (up-down) arrangement is referred to as a column, and a horizontal (horizontal) arrangement is referred to as a row.

[0031] Specifically, the straight pipe sections 21a are arranged at equal vertical intervals (PT), and adjacent straight pipe sections 21a are vertically offset by half a pitch (PT / 2). That is, in FIG. 8, the (N+1)th straight pipe section 21a, counting from the upstream side in the airflow direction, is shifted downward by half a pitch from the Nth straight pipe section 21a. Similarly, the (N+2)th straight pipe section 21a, counting from the upstream side in the airflow direction, is shifted upward by half a pitch (PT / 2). In other words, as shown in FIGS. 8 and 9, rows of odd-numbered straight pipe sections 21a and rows of even-numbered straight pipe sections 21a, counting from the upstream side in the airflow direction, are vertically aligned at equal intervals. This increases the airflow contacting the straight pipe sections 21a, thereby improving cooling efficiency.

[0032] In contrast, the straight portions 223a of the upper piping 223 extending in the horizontal direction are arranged between the straight piping portions 21a at a lower density (the number of straight portions 223a penetrating the fins 22 per unit area as viewed in the direction in which the straight portions 223a extend; the same applies below) than the straight piping portions 21a. Specifically, a straight portion 223a is arranged between the Nth straight piping portion 21a and the (N+1)th straight piping portion 21a, counting from the upstream side in the air flow direction, but a straight portion 223a is not arranged between the (N+1)th straight piping portion 21a and the (N+2)th straight piping portion 21a, counting from the upstream side in the air flow direction. Similarly, a straight section 223a is arranged between the (N+2)th straight piping section 21a and the (N+3)th straight piping section 21a, counting from the upstream side in the air flow direction, but no straight section 223a is arranged between the (N+3)th straight piping section 21a and the (N+4)th straight piping section 21a, counting from the upstream side in the air flow direction. It is preferable that the straight section 223a be arranged at an intermediate position between the straight piping sections 21a arranged in the air flow direction. By thinning out the number of straight sections 223a relative to the number of straight piping sections 21a in this way, the heat exchanger 20 is not overheated when high-temperature hot gas flows through the straight sections 223a, and the generation of haze can be suppressed. For example, in this embodiment, a straight portion 223a is arranged between the first and second straight piping portions 21a, counting from the upstream side in the air flow direction, but no straight portion 223a is arranged between the second and third straight piping portions 21a. Also, a straight portion 223a is arranged between the third and fourth straight piping portions 21a, counting from the upstream side in the air flow direction, but no straight portion 223a is arranged between the fourth and fifth straight piping portions 21a, counting from the upstream side in the air flow direction.

[0033] However, it is preferable to arrange the straight sections 223a adjacent to the first and last rows of straight piping sections 21a in the air flow direction (more inward or closer to the center of the fins 22). That is, it is preferable to make the density of the straight sections 223a in the areas near the first and last rows of straight piping sections 21a in the air flow direction higher than the density of the straight sections 223a in other areas (more inward or closer to the center of the fins 22). Because frost and ice tend to accumulate on both the air intake side and the air discharge side, arranging the straight sections 223a in positions close to these sides allows for efficient melting by hot gas. Note that vertical sections 223b extending in the vertical direction can also be connected to the straight piping sections 21a.

[0034] In particular, in this embodiment, the density of the straight portions 223a below the vertical middle position of the fin 22 is higher than the density of the straight portions 223a above the vertical middle position of the fin 22. Specifically, the straight portions 223a in the region below the vertical middle position of the fin 22 are arranged between the straight pipe portions 21a in the odd-numbered columns (or even-numbered columns). However, the straight portions 223a in the region above the vertical middle position of the fin 22 are arranged between the straight pipe portion 21a in the Lth row and the straight pipe portion 21a in the (L+1)th row, counting from the bottom, in the odd-numbered columns, but are not arranged between the straight pipe portion 21a in the (L+1)th row and the straight pipe portion 21a in the (L+2)th row.

[0035] During defrosting, air heated by hot gas passing through the straight portions 223a in the lower region moves upward due to convection. Therefore, in the region above the vertical midpoint of the fins 22, the density of the straight portions 223a is reduced to prevent overheating and suppress the generation of haze, while in the region below the vertical midpoint of the fins 22, a large amount of heat is supplied, thereby enhancing the defrosting effect.

[0036] The density of the straight line portions 223a may be set by dividing the fin 22 into multiple regions in the vertical direction, with the density of the straight line portions 223a in the lower region being higher than the density of the straight line portions 223a in the upper region. For example, the density of the straight line portions 223a penetrating through a first region of the fin 22 may be set higher than the density of the straight line portions 223a penetrating through a second region above the first region of the fin 22. The pitch of the straight line portions 223a in the vertical direction may also be set to increase upward.

[0037] The present invention is not limited to the above-described embodiments. Any of the components of the above-described embodiments can be modified within the scope of the present invention. Furthermore, any of the components can be added or omitted from the above-described embodiments. For example, the refrigerant of the present invention may be a fluorocarbon-based refrigerant or CO2.

[0038] This specification includes the disclosure of the following inventions. (First aspect) a housing through which air passes; a fan device including a fan that introduces air into the housing; a heat exchanger disposed within the housing; The heat exchanger has a plurality of fins, a cooling pipe passing through the fins, and a defrosting pipe passing through the fins, A refrigerant cooled below room temperature is supplied to the cooling pipe, and a refrigerant heated above room temperature is supplied to the defrosting pipe, The density of the defrosting pipes that penetrate the first region of the fin is higher than the density of the defrosting pipes that penetrate the second region of the fin that is above the first region. A unit cooler characterized by:

[0039] (Second aspect) the density of the defrosting pipes in a region near the end of the fin in the flow direction of the air passing through the heat exchanger is higher than the density of the defrosting pipes in a region closer to the center of the fin. The unit cooler of the first aspect is characterized by:

[0040] (Third aspect) the cooling pipe has a plurality of straight pipe sections that are arranged in double rows along the air flow direction and penetrate the fins, the defrosting pipe has a plurality of straight portions that pass through the fins, The straight section is arranged between the Nth row of the straight piping section and the (N+1)th row of the straight piping section in the air flow direction, and the straight section is not arranged between the (N+1)th row of the straight piping section and the (N+2)th row of the straight piping section in the air flow direction. The unit cooler according to the first or second aspect, characterized in that:

[0041] (Fourth aspect) The defrosting piping has a first piping system that heats a drain pan of the unit cooler and a second piping system that heats the fins, and the refrigerant that has passed through the first piping system enters the second piping system. The unit cooler according to any one of the first to third aspects, characterized in that: [Explanation of symbols]

[0042] 10 Unit Cooler 12. Case 18 Drain pan 20 Heat exchanger 30 Ducted Fan Module 200 Hot gas piping 210 Lower piping system 220 Upper piping system 223 Upper piping 223a Straight section

Claims

1. a housing through which air passes; a fan device including a fan that introduces air into the housing; a heat exchanger disposed within the housing; The heat exchanger has a plurality of fins, a cooling pipe passing through the fins, and a defrosting pipe passing through the fins, A refrigerant cooled below room temperature is supplied to the cooling pipe, and a refrigerant heated above room temperature is supplied to the defrosting pipe, The density of the defrosting pipes penetrating the first region of the fin is higher than the density of the defrosting pipes penetrating the second region of the fin above the first region. A unit cooler characterized by:

2. the density of the defrosting pipes in a region near the end of the fin in the flow direction of the air passing through the heat exchanger is higher than the density of the defrosting pipes in a region closer to the center of the fin.

2. The unit cooler according to claim 1.

3. the cooling pipe has a plurality of straight pipe sections that are arranged in double rows along the air flow direction and penetrate the fins, the defrosting pipe has a plurality of straight portions that pass through the fins, The straight section is arranged between the Nth row of the straight piping section and the (N+1)th row of the straight piping section in the air flow direction, and the straight section is not arranged between the (N+1)th row of the straight piping section and the (N+2)th row of the straight piping section in the air flow direction.

2. The unit cooler according to claim 1.

4. The defrosting piping includes a first piping system for heating a drain pan of the unit cooler and a second piping system for heating the fins, and the refrigerant that has passed through the first piping system enters the second piping system.

2. The unit cooler according to claim 1.

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