JP4035869B2 - Heat exchanger with multiple paths of serpentine tubes - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention has a rectangular path group consisting of a meandering pipe and occupying a plurality of adjacent paths occupying a small rectangular area, and is arranged in a circular cross-sectional flow path of wind blown from a turbofan About.
[0002]
[Prior art]
Conventionally, as an example of this type of heat exchanger, a shunt connected to the tip of a large-diameter inlet pipe, and a base end is connected to the shunt, enters from the inlet at the upper end, and forms an inverted U shape at the upper end. , 4 meandering pipes that form a group of rectangular paths as a whole, forming a small rectangular path that is successively adjacent in the horizontal direction while repeating the vertical meandering that bends in a U-shape at the lower end to the exit at the lower end And what consists of many fins which connect these meandering pipes to the horizontal direction, and the header connected to the exit of the said meandering pipe is known.
The heat exchanger is arranged in a flow passage having a circular cross section of the wind blown from the turbo fan, and the liquid refrigerant flowing into the inlet pipe is distributed to each meander pipe through the flow divider, where it evaporates. Then, heat is taken from the wind, that is, the room air through the fins, becomes a gas refrigerant, merges at the header, and then leaves the heat exchanger.
[0003]
By the way, the circular cross section of the blown air from the turbo fan is in a positional relationship so as to be inscribed in the rectangular path group of the heat exchanger. Faster and slower in the center. Therefore, among the four small rectangular paths constituting the rectangular path group, two of the central part, that is, the central part, mainly exchange heat with room air having a low wind speed over the entire area, and the outer peripheral part, that is, the two at both ends are Heat exchange is performed mainly with room air having a high wind speed in a part of the area.
[0004]
[Problems to be solved by the invention]
However, for each path consisting of the above-described conventional meandering pipe, the path length (area occupied by the path), the number of meanders and the mutual arrangement form are appropriately determined according to the wind speed distribution of the blown-out wind and the effective heat exchange area of the path. The fact is that such factors are not taken into consideration.
Therefore, in the conventional heat exchanger described above, the refrigerant evaporating performance is reduced, or the area of the superheated steam area of the refrigerant occupying the path area is increased, resulting in insufficient dehumidification of the indoor air. There is a problem that condensation occurs in the passage leading to the air outlet of the machine.
[0005]
Therefore, the object of the present invention is to appropriately determine the path length, the number of meanders and the mutual arrangement form of each path according to the wind speed distribution of the turbofan and the effective heat exchange area of the path, thereby evaporating performance and condensation of the refrigerant. An object of the present invention is to provide a heat exchanger having multiple paths of meandering pipes that can improve performance, prevent the formation of a superheated steam region, prevent condensation in the blowout passage, or reduce the manufacturing cost.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 has a rectangular path group in which a plurality of paths occupying a small rectangular area are arranged adjacent to each other, and a wind blown from a turbofan. A heat exchanger disposed in a flow path having a circular cross section, wherein the length of the path passing through the center of the circular cross section in the path group is short and the length of the path passing through the end of the circular cross section. It is characterized by an increase in length.
[0007]
The blown air from the turbofan flows through the heat exchanger so that the circular cross section passes through the rectangular path group, so the path in the center of the circular cross section effectively performs heat exchange, and circular The path at the end of the cross section effectively exchanges heat only in a part of the area, while the wind speed in the circular cross section is fast at the outer peripheral portion and slow at the central portion. Therefore, it is necessary to exchange a large amount of heat in the central path and a small amount of heat in the end path with respect to the blowing wind.
In the heat exchanger according to claim 1, since the length of the central path is short, the flow path resistance is small and a large amount of refrigerant flows, and the end path is long, so the flow path resistance is large. Since a small amount of refrigerant flows, the heat exchange capacity of the refrigerant flowing through each path is balanced with the heat exchange amount of that path. Therefore, during cooling, the evaporating performance of the refrigerant in each path is improved, the occurrence of the superheated steam region due to the lack of the refrigerant is suppressed, and the blowing air is cooled well, and the passage on the downstream side of the heat exchanger Condensation can be prevented. Further, during the heating, the refrigerant condensing performance in each pass is improved, the generation of the supercooled liquid region due to the refrigerant shortage is suppressed, and the blowing air is heated well.
[0008]
The heat exchanger according to claim 2, wherein the adjacent paths are adjacent to a U-shaped bent portion where an outlet of one path is closest to an inlet of the other path, and each of the paths is a fin Are connected to each other.
[0009]
In the heat exchanger according to claim 2, adjacent paths constituting the rectangular path group are configured such that the exit of one path is adjacent to the U-shaped bent portion closest to the entrance of the other path, and the fins are mutually finned. Since it is connected, the outlet of one path tends to be heated by the superheated steam-like refrigerant during cooling, but is cooled through the fins by the cold liquid refrigerant flowing through the bent part of the other path. The cooling capacity of the entire heat exchanger is improved. On the other hand, at the time of heating, the temperature of the outlet of one path tends to be lowered by the supercooled liquid-like refrigerant, but is heated through the fins by the hot gas refrigerant flowing through the bent part of the other path, so that the heat exchanger The overall heating capacity is improved. Therefore, at the time of cooling, the blown air is more favorably cooled, so that condensation in the passage on the downstream side of the heat exchanger can be prevented, and at the time of heating, the blown air is more favorably heated.
[0010]
[0011]
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is a front view showing an example of a heat exchanger according to claim 1 of the present invention. This heat exchanger has a base end connected to a shunt (not shown) through which refrigerant flows in as shown by an arrow A, and has a vertical meander that enters from the upper end, bends in an inverted U shape at the upper end, and bends in a U shape at the lower end. Repeatedly reaching the exit at the lower end, each forming a small rectangular path that is successively adjacent in the horizontal direction, and the four meandering pipes 1a, 1b, 1c, 1d forming a rectangular path group 1 as a whole, and these meandering pipes 1a, 1b, 1c, and 1d are connected to the outlets of the meandering tubes 1a, 1b, 1c, and 1d, and the header 2 from which the refrigerant flows out as shown by an arrow B is formed.
[0013]
Behind the path group 1 of the heat exchanger, a turbo fan is arranged so that the circular cross section 3 of the blown air is inscribed in the path group 1. From the above characteristics, it is faster at the outer peripheral portion 3b indicated by hatching in the figure and slower at the central portion 3a indicated by dots.
The meandering path 1b, 1c passing through the center of the circular section 3 in the path group 1 has a meandering frequency of only one and a half times, and therefore the path length is short, while the meandering path passes through the end of the circular section. In 1a and 1d, the number of meanders is as large as three and a half, so the path length is also about 2.3 times that of the paths 1b and 1c.
[0014]
The heat exchanger configured as described above operates as follows.
The blown air from the turbofan flows through the heat exchanger perpendicularly to the paper surface of FIG. 1 so that the circular cross section 3 is inscribed in the rectangular path group 1, and therefore the path 1 b at the center of the circular cross section 3. , 1c effectively exchanges heat over almost the entire area, while the paths 1a, 1d at the ends of the circular cross section 3 exchange heat effectively over only part of the area, while the wind speed of the blown air in the circular cross section 3 is as described above. As shown in the figure, it is faster at the outer peripheral portion 3b and slower at the central portion 3a. Therefore, it is necessary to exchange a large amount of heat in the central path 1b, 1c and a small amount of heat in the end path 1a, 1d with respect to the blowing wind.
[0015]
The heat exchanger comprising the rectangular path group 1 has a meandering frequency and path length of the central paths 1b and 1c which are 1 / 2.3 smaller than those of the end paths 1a and 1d. A larger amount of refrigerant flows in the central paths 1b, 1c than in the end paths 1a, 1d, and the amount of refrigerant flowing in each path 1a, 1b, 1c, 1d is necessary for that path. This balances with the heat exchange amount. Therefore, during cooling, the evaporation performance of the refrigerant in each pass 1a, 1b, 1c, 1d is improved, the generation of the superheated steam region due to the lack of refrigerant is suppressed, the blown air from the turbo fan is cooled well, and the pass Condensation in the passage on the downstream side of group 1 is prevented. Further, during heating, the refrigerant condensing performance in each of the paths 1a, 1b, 1c, and 1d is improved, the generation of a supercooled liquid region due to insufficient refrigerant is suppressed, and the blown air from the turbo fan is heated well.
The heat exchanger has an advantage that the header 2 can be shortened because the arrangement of the path group 1 is such that the outlets of the paths 1a, 1b, 1c, and 1d are gathered at the center.
[0016]
FIG. 2 is a front view showing an example of a heat exchanger according to claim 2 of the present invention. In this heat exchanger, the refrigerant inflow ends of the two paths 1a and 1b on the left side of the heat exchanger of FIG. 1 are reversed left and right, and all the paths 1a ', 1b', 1c and 1d enter from the upper right and lower left. The only difference is that the path group 1 ′ exits. In other words, in this heat exchanger, as can be seen from the piping in the vicinity of the header 2, the outlet of one of the adjacent paths 1d, 1c; 1c, 1b ';1b', 1a '(for example, 1d) is the other (for example, 1c). The path is adjacent to the U-shaped bend closest to the entrance, and the paths are connected to each other in the lateral direction by the fins (not shown).
[0017]
The heat exchanger in FIG. 2 operates as follows. In this heat exchanger as well, the path lengths of the central paths 1b ′ and 1c are as short as 1 / 2.3 of the path lengths of the end paths 1a ′ and 1d. Similarly, the amount of refrigerant flowing through 1b ′, 1c, and 1d is balanced with the amount of heat exchange required for the path. In addition, in the adjacent paths, the exit of one path is adjacent to the U-shaped bent portion closest to the entrance of the other path and is connected to each other by fins. Therefore, at the time of cooling, the temperature of the outlet of one path tends to increase due to the superheated steam-like refrigerant, but is cooled via the fins by the cold liquid refrigerant flowing through the bent portion of the other path, so the entire heat exchanger The cooling capacity of the first pass is further improved, and at the time of heating, the temperature at the outlet of one pass tends to be lowered by the supercooled liquid refrigerant, but is heated through the fins by the hot gas refrigerant flowing through the bent portion of the other pass. Therefore, the heating capacity of the entire heat exchanger is further improved. Therefore, at the time of cooling, the blown air is more favorably cooled, so that condensation in the passage on the downstream side of the heat exchanger can be prevented, and at the time of heating, the blown air is more favorably heated.
[0018]
Figure 3 is a front view showing a heat exchanger as a reference example, rather than an embodiment of the present invention. This heat exchanger is similar to the heat exchanger of FIG. 2 in that the U-shaped bent portion where the outlet of one of the adjacent paths 4d, 4c; 4b, 4a (for example, 4d) is closest to the inlet of the other (for example, 4c). 1 in that the two passes 1b, 1c at the center of the heat exchanger in FIG. 1 and the two passes 1a, 1d at the end are made to have the same number of meandering repetitions and the same path length. That is, in this heat exchanger, each of the paths 4a, 4b, 4c, and 4d constituting the path group 4 has a meandering number of two and a half times and substantially the same path length.
[0019]
In the heat exchanger of FIG. 3, each of the paths 4a, 4b, 4c, and 4d constituting the path group 4 has a meandering number of two and a half times and substantially the same path length. Since it can be manufactured using the same bending mold, the manufacturing cost can be reduced. In this heat exchanger as well as the heat exchanger of FIG. 1, the arrangement of the path group 4 is such that the outlets of the paths 4a, 4b, 4c, and 4d are gathered at the center, so the header 2 is shortened. can, as with the heat exchanger of Figure 2, the outlet of one path is adjacent to the nearest U-shaped bent portion to an inlet of the other path, the advantage that you increase the heat exchanger overall heating and cooling capacity is there.
[0020]
Figure 4 is a front view showing a heat exchanger as a reference example, rather than an embodiment of the present invention. In this heat exchanger, each of the paths 4a ′, 4b ′, 4c, and 4d constituting the path group 4 ′ has a path length substantially equal to the number of meanders of two and a half times, as in FIG. The arrangement of 4 'is the same as that of FIG. 2, and one exit of the adjacent paths 4d, 4c; 4c, 4b'; 4b ', 4a' is adjacent to the U-shaped bend closest to the other entrance. ing.
[0021]
Therefore, the heat exchanger of FIG. 4 can be manufactured using the same bending mold by sharing each path as a component, as described in FIG. 3, and thus the manufacturing cost can be reduced and the same as described in FIG. In addition, the outlet side of one path is cooled or heated so as to receive the heat conduction from the refrigerant flowing into the bent part of the other path through the fins and to increase the cooling or heating capacity of the entire heat exchanger. Therefore, although the area of each path is equal, the blown air from the turbofan is cooled well during cooling, and condensation in the passage on the downstream side of the heat exchanger can be prevented. The wind is heated well.
[0022]
The meandering pipe constituting the rectangular path group of the present invention has been described as having a single passage portion in the above embodiment, but the meandering pipe is divided into a plurality of passage portions divided in cross section. It can also be a flat tube or the like.
[0023]
【The invention's effect】
As is apparent from the above description, the invention of claim 1 has a rectangular path group in which a plurality of paths occupying a small rectangular area made up of meandering tubes are arranged side by side, and the wind blown from the turbofan A heat exchanger disposed in a flow passage having a circular cross section, wherein the length of the path passing through the central portion of the circular cross section in the path group is short and the length of the path passing through the end of the circular cross section. Since the length of the heat exchanger is longer, more refrigerant flows through the central path where a larger amount of heat exchange is required, and the heat exchange capacity of each path balances with the required heat exchange amount. In addition, it is possible to cool the blown air from the turbofan well, prevent condensation in the blowout passage, and to heat the blown air well by improving the condensation performance.
[0024]
The heat exchanger according to claim 2, wherein the adjacent paths are adjacent to each other at a U-shaped bent portion where an outlet of one path is closest to an inlet of the other path, and the paths are mutually connected by fins. Since it is connected, the outlet side of one path receives heat conduction from the refrigerant flowing into the bent part of the other path through the fins so that the cooling capacity or heating capacity of the entire heat exchanger is improved. Since it is heated, it is possible to cool the blown air from the turbo fan more satisfactorily, prevent condensation in the blow passage, and further heat the blown air.
[0025]
[Brief description of the drawings]
FIG. 1 is a front view showing an example of a heat exchanger according to claim 1 of the present invention.
FIG. 2 is a front view showing an example of a heat exchanger according to claim 2 of the present invention.
FIG. 3 is a front view showing a heat exchanger according to a reference example of the present invention.
FIG. 4 is a front view showing a heat exchanger according to a reference example of the present invention.
[Explanation of symbols]
1 ... path group, 1a, 1b, 1c, 1d ... path of meander pipe, 2 ... header,
3 ... Circular cross section of blown air from turbo fan, 4 ... Pass group,
4a, 4b, 4c, 4d ... path of meandering pipe.

Claims (2)

It has a rectangular path group (1) in which a plurality of (1a, 1b, 1c, 1d) paths that occupy a small rectangular area are arranged side by side, and has a circular cross section of wind blown from a turbofan ( 3) a heat exchanger disposed in the flow path;
The path (1b, 1c) passing through the center of the circular cross section (3) in the path group (1) is short and the path (1a, 1d) passing through the end of the circular cross section (3). The heat exchanger is characterized in that its length is longer.   The heat exchanger according to claim 1, wherein the adjacent paths (1d, 1c; 1c, 1b '; 1b', 1a ') have an outlet of one path (1d) of the other path (1c). A heat exchanger characterized in that it is adjacent to a U-shaped bent portion closest to the inlet, and each of the paths (1a ', 1b', 1c, 1d) is connected to each other by fins.

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