Bottom plate structure of heat exchanger

Abstract

To provide a fin-and-tube heat exchanger that has a bottom plate structure in which in order to reduce pressure loss of an airflow, drain holes are provided in a bottom plate of the heat exchanger to drain condensation water from the drain hole, and which prevents deterioration in heat exchange performance.SOLUTION: In a bottom plate that receives condensation water from coils and fins of a fin-and-tube heat exchanger, drain holes are provided in the bottom plate for condensation water generated during cooling, where the drain holes include at least drain holes near a center part of the bottom plate and drain holes near a downstream terminal, where a diameter of the drain holes near the terminal is made larger than a diameter of the drain holes near the center part; the number of drain holes near the terminal is made larger than the number of drain holes near the center part; or both of these are combined.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a fin-and-tube heat exchanger that reduces the pressure loss of air flow, and more particularly to a bottom plate structure of the heat exchanger. [Background technology]

[0002] Conventional fin-and-tube heat exchangers are known to have a structure in which the coil is covered with a frame, as shown in Figure 1, to protect the fins and main pipe of the coil and to ensure the passage of target fluids such as air. Generally, as shown in Patent Document 1, a drain pan (see dotted line area 212 in Figure 1) is placed under the coil to collect condensed water such as condensation, and condensed water that falls from the bottom plate of the coil is drained mainly from the drain pan. In such fin-and-tube heat exchangers, in order to drain the condensed water that condenses on the cooled fins and main tubes of the coil during cooling or dehumidification operations, drainage holes are provided in the bottom plate and the condensed water is drained through the drainage holes. However, when condensed water accumulates on the surface of the bottom plate of the coil of a heat exchanger or on the coil, the condensed water accumulated at the most downstream part of the air flow is scattered, or the condensed water accumulates on the bottom plate, increasing the pressure loss. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-30659 A Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a bottom plate structure in the above-mentioned fin-and-tube heat exchanger, in which drainage holes are provided in the bottom plate of the heat exchanger, so that condensed water can be drained through the drainage holes, thereby reducing pressure loss without degrading heat exchange performance. [Means for solving the problem]

[0005] In order to achieve the above object, the bottom plate structure of the heat exchanger has a drain hole for condensation water generated during cooling in the bottom plate that receives condensation water from the coils and fins provided in the coil of the heat exchanger. In addition, the number and groups of drainage holes provided in the bottom plate are greater the further downstream, and / or the hole diameter of the drainage holes is larger the further downstream, and further, the drainage holes are provided at least near the center of the bottom plate and near the downstream end, and the hole diameter of the drainage holes near the end is larger than the hole diameter of the drainage holes near the center. The size of the hole diameter of the drainage holes and the number of the drainage holes may be appropriately combined to efficiently drain the condensed water and suppress the amount of bypass air. Effect of the Invention

[0006] According to the bottom plate structure of the heat exchanger of the present invention, the bottom plate that receives condensed water from the main pipes and fins of the heat exchanger coil is provided with drainage holes for condensed water generated during cooling, and the number of drainage holes increases toward the downstream side and / or the hole diameter increases, so that the condensed water accumulated on the bottom plate can be properly drained while maintaining the heat exchange performance of the heat exchanger. This makes it possible to reduce the pressure loss (approximately 5% in Figure 6) while maintaining the heat exchange performance. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a perspective view of the overall appearance of a heat exchanger according to the embodiment; [Diagram 2] FIG. 2(a) is a diagram showing the state of condensed water in a conventional bottom plate without a drain hole, and FIG. 2(b) is a diagram showing the state of condensed water in a bottom plate having a drain hole only provided near the center of the bottom plate according to an embodiment of the present invention. [Diagram 3] FIG. 3(a) is a diagram explaining the state of condensed water when the number of rows of the coil main pipes is large (in the direction of the wind flow on the bottom plate) and a drain hole is provided only near the center of the bottom plate. FIG. 3(b) is a diagram explaining the state of condensed water when a drain hole is provided only near the leeward end of the bottom plate. [Figure 4] 4(a) to (c) are diagrams for explaining another embodiment of the present invention, in which drainage holes 27 with the same hole diameter are provided at least near the center and near the leeward end of the bottom plate. FIG. 4(d) to (f) are diagrams for explaining another embodiment of the present invention, in which drainage holes 27 with different hole diameters are provided at least near the center and near the leeward end of the bottom plate. [Diagram 5] FIG. 2 is a diagram of a bottom plate structure according to an embodiment of the present invention, illustrating the state of bypass airflow and the state of condensed water; [Figure 6] Graph 1 shows a comparison of coil performance and pressure loss between a conventional bottom plate structure with a drain hole in the center (bottom plate in Fig. 2(b)) and the present invention, in which drain holes are provided near the center and near the downwind end of the bottom plate (Fig. 5). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The present invention relates to a bottom plate structure in which drainage holes are provided in the bottom plate of a fin-and-tube heat exchanger to drain condensed water such as condensation from the drainage holes in order to prevent a decrease in coil performance, and which reduces pressure loss without a decrease in heat exchange performance. A preferred embodiment of the present invention will be described with reference to the drawings. EXAMPLES

[0009] First, the necessity of the drain hole will be explained. 1 shows a fin-and-tube heat exchanger 1, in which a coil 2 is mounted on a frame 21, a header 22 is provided on one side of the coil 2, a main pipe 25 of the coil is connected to the header 22, and the main pipe 25 is folded back to the header 22 at a U-bend 26 on the other side, and a bottom plate 211 is provided on the coil frame 21. The header 22 has a header portion on the side of a cold / hot water inlet 221 and a cold / hot water outlet 222, and a cold / hot water inlet 23 and a cold / hot water outlet 24 are provided on the side of the cold / hot water inlet 221 and the side of the cold / hot water outlet 222 of this header portion, and are connected to the main pipe 25. If necessary, a drain pan 212 for temporarily storing drainage such as condensation is provided further below the bottom plate 211.

[0010] In the absence of a conventional drain hole, as shown in FIG. 2(a), condensed water A accumulates on the bottom plate 211 below the group of coils 2 of the heat exchanger 1, restricting the flow path of the air, resulting in inconveniences such as a decrease in the heat exchange performance of the coils and an increase in pressure loss. In addition, there is a concern that the accumulated condensed water will scatter downstream, causing problems such as water leakage downstream. In this case, as shown in FIG. 2(b), providing a drain hole 27 near the center of the bottom plate 211 is effective when the number of rows of coils is small, as it allows the water to be drained at all times. However, with a single row of drain holes near the center, the air to be cooled will flow together with the drainage and bypass the air, causing inconveniences such as a decrease in heat exchanger performance in this case as well. However, when the number of coil rows increases, drainage holes near the center are insufficient for draining condensed water, and the condensed water is retained on the bottom plate 211, preventing air from passing through the fin surface, resulting in increased pressure loss and reduced heat exchange performance of the coil. If we consider the case where there are many rows in the direction perpendicular to the air flow, if drainage holes 27 are provided near the center of bottom plate 211, the amount of condensed water A will increase as shown in Figure 3(a), and while the condensed water A near the center will be drained, the condensed water A on the downwind side will not be drained, causing a puddle of condensed water A, which will impede the air flow and increase pressure loss, as well as increasing the possibility of condensed water A scattering. Furthermore, if the drain hole 27 is provided on the leeward side, as shown in FIG. 3(b), the condensed water A on the leeward side is discharged, but conversely, the condensed water A accumulates on the windward side from the vicinity of the center, leading to an increase in pressure loss.

[0011] Therefore, in the present invention, rows of drainage holes 27 are provided at least near the center and near the end on the downwind side, and some embodiments thereof will be described with reference to FIG. Figures 4(a) to (c) are plan views of the bottom plate 211, with drainage holes 27 of the same diameter arranged in one row, and Figure 4(a) has six drainage holes 27 arranged near the center and 11 drainage holes 27 arranged near the leeward end, and Figure 4(b) has six drainage holes 27 arranged near the center and 11 drainage holes 27 arranged near the leeward end, but the only difference from Figure 4(a) is that the bottom plate is wider. Figure 4(c) has three rows of drainage holes 27, six drainage holes 27 arranged near the center and 11 drainage holes 27 arranged in the middle between the leeward end and the center.

[0012] Similarly, in Figures 4(d) to (e), the hole diameter of the drainage holes 27 near the downwind end is made larger than that of the drainage holes 27 near the center, and in Figures 4(d) to (f), eleven drainage holes 27 with larger hole diameters than those of the drainage holes 27 near the center are lined up near the downwind end, and the width of the bottom plate is changed as in Figures 4(a) to (c). In addition, the reason for increasing the number of holes or increasing the diameter of the drainage holes 27 on the leeward side is that the mass of water is greater than that of air, so air can easily pass through the first drainage holes 27, while the holes near the ends are suitable for draining the large mass of water due to the wind speed.

[0013] For these reasons, as shown in Figure 5, in a fin-and-tube heat exchanger, by appropriately selecting the number, hole diameter, and arrangement (density) of the drainage holes 27 near the center and the drainage holes 27 near the downwind end, the amount of bypass air B can be reduced, thereby preventing a decrease in heat exchange performance. In addition, the drainage of the condensed water 27 is improved and pooling of water can be suppressed, thereby reducing pressure loss and allowing the condensed water A to be properly discharged.

[0014] Graph 1 in Fig. 6 compares the number and size of the drainage holes 27 of the present invention with the embodiment in Fig. 4(e) in a conventional bottom plate 211 with a single row of drainage holes in the middle. Specifically, the embodiment has 6 drainage holes 27 in the center and 11 drainage holes 27 near the ends, with the hole diameter of the drainage holes 27 near the ends being larger, and while suppressing the deterioration of heat exchange performance due to an increase in the airflow (bypass air B) that does not pass through the heat exchanger 1, the drainage performance is improved, and pressure loss can be reduced by suppressing water pooling. In other words, the drainage performance of the drainage holes is improved, heat exchange performance equivalent to that of the conventional product is maintained, and pressure loss is reduced by about 5%.

[0015] As described above, according to the bottom plate structure of the heat exchanger of the embodiment of the present invention, the bottom plate that receives the condensed water from the coils and fins of the heat exchanger coil is provided with drainage holes for the condensed water generated on the bottom plate, and the number of the drainage holes increases toward the downstream side, and the hole diameter is made larger, so that the condensed water accumulated on the bottom plate can be properly discharged while maintaining the heat exchange performance of the heat exchanger. Also, the pressure loss can be reduced (about 5% in Figure 6) while maintaining the heat exchange performance. [Explanation of symbols]

[0016] A: Condensate, B: Bypass air 1...heat exchanger, 2 coil, 21 coil frame, 211 bottom plate, 212 drain pan 22 Header, 221 Cold / hot water inlet header, 222 Cold / hot water outlet header, 23··Hot and cold water inlet, 24··Hot and cold water outlet, 25··Main pipe, 26··U-bend, 27...drain hole, 3. Fins

Claims

1. In the bottom plate that receives condensate from the coils and fins of a fin-and-tube heat exchanger, A bottom plate structure for a heat exchanger, characterized in that a drain hole is provided for condensed water generated on the bottom plate, thereby allowing the condensed water to be constantly drained.

2. 2. The bottom plate structure of a heat exchanger according to claim 1, wherein the number of the drain holes and / or the diameter of the drain holes are increased toward the downstream side.

3. The bottom plate structure of a heat exchanger as described in claim 2, characterized in that the drainage holes include a drainage hole near at least the center of the bottom plate and a drainage hole near the downstream terminal, and the number of drainage holes near the terminal is greater than the number of drainage holes near the center.

4. The bottom plate structure of a heat exchanger as described in claim 2, characterized in that the drainage holes include a drainage hole near at least the center of the bottom plate and a drainage hole near the downstream end, and the hole diameter of the drainage hole near the end is larger than the hole diameter of the drainage hole near the center.

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