JP2016133247A - Heat exchanger and refrigeration cycle device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently uniformize wind speed distribution of a heat exchanger having a bending part.SOLUTION: A heat exchanger unit includes: a fin tube heat exchanger including a fin group formed by laminating plate-like fins and fluid pipelines penetrating through the fin group, the fin tube heat exchanger configured to conduct heat exchange between air and a fluid; and a blower for circulating air between the fins. Each fluid tube has a bending part. A part of the bending part is formed so as not to have fins to reduce draft resistance in the bending part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat exchanger and a refrigeration cycle apparatus using the heat exchanger.

  Some heat pump type heating devices or air conditioners based on the refrigeration cycle have a fin tube type heat exchanger that evaporates or condenses the refrigerant by exchanging heat with air. There is a technique of securing a heat transfer area by bending a part into an L shape. However, in such a configuration, there has been a problem that the wind speed of the bent portion of the heat exchanger is lower than that of the straight portion, and the air volume of the entire heat exchanger is reduced due to non-uniform wind speed distribution.

  On the other hand, the thing which aimed at equalization of wind speed distribution by making the fin pitch of the bent part of a heat exchanger wider than a straight part conventionally is proposed.

  Patent Document 1 discloses a fin tube-type heat exchanger formed in a substantially L shape in which the fin pitch of the bent portion is larger than the fin pitch of other portions.

  Moreover, in patent document 2, the ventilation direction downstream end part of the fin which comprises the bending part of a heat exchanger has a ventilation direction upstream rather than the ventilation direction downstream end part of the fin which comprises the linear part of a heat exchanger. What has the recessed part dented in the side is disclosed.

JP 2008-70045 A JP 2010-151403 A

  Considering the realization of the technique described in Patent Document 1, since there are a plurality of types of rising widths of the fin collar, a plurality of press dies for manufacturing the fins are required, and the equipment cost increases. In addition, when the fins are manufactured using the same press machine, the molds need to be recombined, so that the manufacturing efficiency is lowered. From the above, in the prior art, the manufacturing cost for obtaining a uniform wind speed distribution increases, so there remains room for improvement in performance with respect to cost.

  As in the technique described in Patent Document 2, even if a recess is provided at the downstream end of the fin constituting the bent portion of the heat exchanger in the air blowing direction, the fin of the portion is crushed and the air flow path is narrowed. The problem is not solved sufficiently.

  Then, an object of this invention is to fully equalize the wind speed distribution of the heat exchanger which has a curved part.

  The present invention includes a fin group heat exchanger that includes a fin group in which plate-like fins are stacked and a plurality of fluid pipes that penetrate the fin group, and performs heat exchange between air and fluid, and distributes air between the fins. A heat exchanger unit including a blower, wherein the fluid piping has a bent portion, and a portion of the bent portion does not have a fin, thereby reducing the ventilation resistance of the bent portion. It is.

  ADVANTAGE OF THE INVENTION According to this invention, the wind speed distribution of the heat exchanger which has a curved part can fully be equalize | homogenized.

It is a schematic diagram showing the overall system of CO ₂ heat pump water heater. It is a top view which shows the structure inside the heat pump unit containing the evaporator 103 of FIG. It is a perspective view which shows the evaporator of Example 1. FIG. It is a fragmentary perspective view which shows the dimension in the state which accumulated two fins of the evaporator. It is a top view which shows the conventional evaporator (comparative example 1). It is a perspective view which shows the conventional evaporator (comparative example 1). It is a graph which shows the wind speed distribution in the evaporator of Example 1 of FIG. 2 and the comparative example 1 of FIG. 5A. It is a top view which shows the evaporator by the prior art described in patent document 1. FIG. It is a top view which shows the evaporator of Example 2. FIG. It is a top view which shows the structure inside the heat pump unit containing the evaporator of Example 3. FIG. It is a graph which shows the wind speed distribution in the evaporator of Example 3 and Comparative Example 2 of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  A first embodiment will be described with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing the entire system of a heat pump water heater using carbon dioxide (CO ₂ ) as a refrigerant.

  In this figure, the heat pump water heater includes a heat pump cycle 200 and a water-side cycle 201 that operate during heating from cold water to hot water, and a hot water supply channel group that operates during hot water supply.

  The heat pump cycle 200 has a configuration in which elements of the compressor 100, the water refrigerant heat exchanger 101, the expansion valve 102, and the evaporator 103 are connected in an annular shape. On the other hand, the water-side cycle 201 has a configuration in which the hot water storage container 104, the boiling circulation pump 105, and the water refrigerant heat exchanger 101 are connected in an annular shape. The hot water supply channel group includes a hot water supply cycle 202 in which a hot water storage container 104, a hot water supply circulation pump 106, and a hot water supply heat exchanger 107 are connected in an annular manner, a water pipe 108, a hot water supply heat exchanger 107, and a hot water supply port 109 in series. It is composed of connected flow paths.

In the present embodiment, CO ₂ refrigerant is sealed in the heat pump cycle 200, and the water-side cycle 201 and the hot water supply cycle 202 are filled with water. Further, in order to fill the hot water supply cycle 202 with water, a water pipe 108 is connected to the lower part of the hot water storage container 104.

  FIG. 2 is a plan view showing the arrangement of the evaporator 103 in FIG. 1 inside the heat pump unit.

  As shown in the figure, the evaporator 103 is arranged in an L shape along the periphery of the heat pump unit 20. And the axial flow fan 21 is arrange | positioned on the opposite side of the L-shaped evaporator 103, and the partition plate 22 is arrange | positioned on the side surface of the axial flow fan 21, and the air path from the evaporator 103 to the axial flow fan 21 is comprised. doing.

FIG. 3 shows a perspective view of the evaporator 103. The evaporator 103 is a fin tube type heat exchanger that is disposed so as to pass through the refrigerant pipe 9 through which the CO ₂ refrigerant flows with respect to the fin 6 that is a heat transfer surface of air. Here, the refrigerant pipe 9 has a circular tube shape.

  The refrigerant pipe that penetrates the evaporator 103 is connected in a hairpin shape at the end of the evaporator 103, but the refrigerant inlet 10 that allows the refrigerant from the expansion valve 102 to flow into a part of the end, and the compressor A refrigerant outlet portion 11 for allowing the refrigerant to flow out to 100 is provided.

  The evaporator 103 according to the present embodiment includes three rows of fins 6 and refrigerant pipes 9 with respect to the direction of air flow, and only the column on the most downstream side of the air (the column with the smallest radius of curvature) is the bent portion of the evaporator. The fins 6 are not provided, and only the refrigerant pipe 9 is exposed.

  In this specification, the column of refrigerant tubes in the evaporator (fin tube heat exchanger) is orthogonal to the direction of the general air flow indicated by the solid line arrow in FIG. 2 unless otherwise specified. This means that a plurality of refrigerant tubes are arranged so that the central axes of the plurality of refrigerant tubes are positioned on a plane. Therefore, a fin tube type heat exchanger having a plurality of refrigerant tube rows is formed by arranging a plurality of refrigerant tube rows from the upstream side to the downstream side with respect to the air flow. In FIG. 3, the fin group corresponding to each one row of the refrigerant tubes constituting the plurality of rows is in a state of being separated for each row, but the configuration of the fin group is not limited to this. Instead, it may have a configuration in which a plurality of rows of refrigerant tubes are inserted into one fin.

  A plurality of refrigerant tubes arranged in a staggered arrangement may be regarded as one row.

  The main point of the present invention is that a part of the refrigerant pipe located in the bent portion has no fin, and the position is not limited to the most downstream line of air. However, in consideration of how the distance between the fins is reduced, it is desirable not to provide fins in the refrigerant pipe having a small curvature radius.

  FIG. 4 is a perspective view showing a state in which two fins 6 are stacked. The fin 6 includes a fin plate portion 7 and a fin collar portion 8 having a height H that covers the refrigerant pipe 9. And the fin group is comprised by laminating | stacking the fin 6 on the edge part of the fin collar part 8. FIG. Therefore, the fin pitch p depends on the color height H. The fin pitch p is a distance between the surfaces of the two adjacent fin plate portions 7 facing in the same direction (may be a distance between the center lines of the cross sections in the thickness direction). Is a value measured in a state where the heat exchanger (evaporator 103) is completed.

  Regarding the first embodiment, the operation of the system will be described.

After the CO ₂ refrigerant is compressed by the compressor 100 to a high temperature / high pressure state, the water refrigerant heat exchanger 101 heats the cold water sent from the lower part of the hot water storage container 104 by the boiling circulation pump 105 to the cold water. And loses its own heat instead of heating to warm water. Then, after passing through the expansion valve 102, the refrigerant enters a low temperature / low pressure state, receives heat from the air sent by the axial fan 21 in the evaporator 103, and flows into the compressor 100 again. In the water-refrigerant heat exchanger 101, water and the refrigerant flow in opposite directions, and the heated hot water is returned to the upper part of the hot water storage container 104.

  During the hot water supply operation, the hot water supply circulation pump 106 is operated, hot water is supplied from the upper part of the hot water storage container 104 to the hot water supply heat exchanger 107, and at the same time, tap water is supplied from the water pipe 108. In the hot water supply heat exchanger 107, tap water flows in a direction opposite to the hot water from the hot water storage container 104, receives heat, and then is supplied to the hot water supply port 109. Further, the water from the hot water storage container 104 that has lost heat in the hot water supply heat exchanger 107 returns to the lower part of the hot water storage container 104.

  Next, the operation of the evaporator 103 will be described with reference to FIGS.

  When the axial fan 21 is driven, air flows through the evaporator 103 toward the axial fan 21 (solid arrow in FIG. 2). When this air passes through the gaps between the fin groups, it heats the refrigerant flowing in the direction of the broken arrow through the fin plate portion 7 and the fin collar portion 8. In FIG. 2, the flow of the refrigerant is shown from right to left in the drawing for the sake of simplicity, but actually, the refrigerant is folded at the end of the evaporator 103 as indicated by a broken line in FIG. 3. Circulate.

  In order to explain the effect of the present invention, first, a general evaporator 103 will be described.

  5A and 5B are a plan view and a perspective view of a conventional general evaporator 103, respectively. In these drawings, the evaporator 103 is configured in three rows as in this embodiment, and fins 6 having fin collar portions having a constant height are arranged in all rows.

  FIG. 6 is a graph showing the wind speed distribution in the evaporator of Example 1 of FIG. 2 and Comparative Example 1 of FIG. 5A.

  Example 1 is indicated by a solid line. On the other hand, Comparative Example 1 shows the wind speed distribution of the evaporator when the evaporator 103 of FIG. 5A is applied to the heat pump unit 20 of FIG. 2 and the axial fan 21 is driven, and is indicated by a broken line. The horizontal axis is the length from the reference point A shown in FIG. 5A, and the vertical axis is the average wind speed. The fin pitch is 1.3 mm in both Example 1 and Comparative Example 1. FIG. 6 is simplified for easy understanding of actual test results.

  From FIG. 6, it can be seen that the comparative example 1 indicated by the broken line has the highest wind speed on the evaporator back surface 1 and the wind speed of the evaporator bent portion 3 is lower than that on the evaporator back surface 1. This is because the ventilation area becomes narrower as it goes from the outside to the inside of the bent portion 3 of the evaporator, and the ventilation resistance increases due to the fin pitch becoming denser toward the inside of the curved surface.

  Consider the air volume of the entire heat exchanger when the wind speed distribution as shown by the broken line in FIG.

  The ventilation resistance is generally proportional to the wind speed exceeding 1.0 to 1.5, depending on the flow state.

  That is, the ventilation resistance R is expressed by the following equation, where u is the wind speed and n is an index.

R∝u ⁿ (1.0 <n ≦ 1.5)
Therefore, when high wind speed and low wind speed occur, the resistance to air flow increases greatly at the high wind speed compared to the rate of decrease in the wind resistance at the low wind speed. As a result, the air volume decreases. On the other hand, in Example 1 indicated by the solid line in FIG. 6, since the ventilation resistance of the evaporator bent portion 3 is reduced, the wind speed of the portion increases. Along with this, although the wind speed on the evaporator back surface 1 and the evaporator side surface 2 is slightly reduced, the air volume increases as a whole heat exchanger.

  Next, the difference between the present invention and the prior art will be described.

  In FIG. 7, the top view of the evaporator by the prior art described in patent document 1 is shown. In this prior art, the air gap distribution is made uniform as in the present invention by widening the fin interval (p2) of the bent portion 3 of the evaporator as compared with the other portion (p1). This is different from the present invention in that two different types of fins 6 are used.

  In general, the fin 6 is continuously manufactured by installing a fin mold in a press machine and passing a metal flat plate as a raw material through the press machine. In order to prepare fins 6 having different color heights, fin types are required for the types of fins 6 to be manufactured. Therefore, in order to manufacture the prior art evaporator 103, at least two types of fin types are required, and the fixed cost increases. In addition, when the number of the press machines is one, the production efficiency is lowered because the fin mold is exchanged during the manufacturing process. On the other hand, when a plurality of press machines are arranged, the equipment cost is increased. From the above, the cost for obtaining the effect of the conventional technology increases, and there remains a problem in performance with respect to the cost.

  On the other hand, in the present invention, in the step of sequentially superimposing the fins 6 on the refrigerant pipe 9 (fluid piping), a jig is inserted in a portion where the fins 6 are not disposed, and is removed after bending. Can be manufactured. Here, as a jig, a tool corresponding to the length of the portion where the fins 6 are not arranged may be inserted from the side of the refrigerant pipe 9 in the process of superposing the fins 6. A part may be replaced with a jig and arranged, and the jig may be overlaid on the part where the fins 6 are not arranged.

  As another method, a plurality of refrigerant tubes 9 (fluid piping) are set in a straight state in an arrangement corresponding to the fin tube heat exchanger to be manufactured, and fins are overlaid on the group of fluid pipings. Create an integrated finned tube heat exchanger by stacking fins that are cut out from the area of the bent part without fins so that the fin does not enter the part corresponding to the bent part without fins. Can do. In other words, it is possible to manufacture a finned tube heat exchanger having a configuration in which a plurality of rows of refrigerant tubes are inserted into one fin. That is, the fin group can be manufactured without forming a plurality of rows.

  By manufacturing as described above, an effect can be obtained with a slight investment, and the performance with respect to the cost can be improved.

  As described above, according to the present invention, an increase in the air volume by making the wind speed distribution uniform can be realized at low cost. In this embodiment, the number of columns of the evaporator 103 is three. However, if the number of the columns is constituted by a plurality of columns, the effect can be obtained regardless of the number of columns. Further, in the present embodiment, the most downstream side of the air in the evaporator bent portion 3 is a row without the fins 6, but the evaporator bent portion 3 on the air inflow side or the intermediate row may be a row without the fins 6. The intended effect can be obtained.

  A second embodiment will be described with reference to FIG.

  In the present embodiment, with respect to the first embodiment, the refrigerant pipe 9 excluding the fins 6 located on the most downstream side of the air is brought into contact along the inner peripheral side of the fins 6 in the intermediate row.

  The effect of the present embodiment will be described.

  In Example 1, considering that a low-temperature refrigerant flows through the refrigerant pipe and air having a higher temperature than the refrigerant passes between the fins, the surface temperature of the fin plate portion 7 is affected by the influence of heat conduction. The closer to 8, the lower, and the higher the end of the fin plate portion 7, the higher. Therefore, at the end of the fin plate portion 7, the temperature difference from the air is reduced, so that the amount of exchange heat per area is relatively small with respect to the fin collar portion 8.

  On the other hand, when the refrigerant tube 9 in the row without the fin 6 is brought into contact with the end of the fin plate portion 7 in the intermediate row, the end of the fin plate portion 7 in the intermediate row is cooled by the refrigerant tube 9, The difference in heat exchange temperature with air is increased, and as a result, the amount of exchange heat is increased, that is, fin efficiency is improved.

  The shape of the present embodiment can be realized by, for example, bending the linear evaporator 103 with the fins 6 inside the evaporator bending section 3 removed by a processing machine provided with a protrusion that presses the refrigerant tube 9 against the intermediate row.

  With the above mechanism, a heat exchanger with higher performance can be obtained with the same processing cost as in the first embodiment. In this embodiment, the refrigerant pipe on the most downstream side of the air is brought into contact with the inner side of the intermediate row, but if a part of the refrigerant pipe is in contact with the fin end, the intended effect of the present invention is achieved. Is obtained.

  A third embodiment will be described with reference to FIG.

  In the present embodiment, the shape of the evaporator 103 is different from the configuration of the first embodiment.

FIG. 9 shows a layout diagram of the evaporator 103. The evaporator 103 is arranged in a U shape over three surfaces of the heat pump unit 20, and the partition plate 22 and the axial fan 21 constitute an air path.
The basic configuration of the evaporator 103 is the configuration in which the refrigerant pipe 9 penetrates the fin 6 as in FIG. 3, but there are two bent portions, and only the evaporator bent portion 3 closer to the axial fan 21 has air There is no fin 6 on the most downstream side.

  FIG. 10 shows the wind speed distribution when this embodiment is used. The broken line in the figure indicates the wind speed distribution (Comparative Example 2) when fins are also present in the evaporator bent portion 3, and the solid line indicates the wind speed distribution when the structure shown in FIG. 9 is used.

  From FIG. 10, it can be seen that also in the present embodiment, the wind speed of the evaporator bent portion 3 is increased by the same principle as in the first embodiment, and the wind speed distribution is improved.

  The evaporator second bent portion 5 also has an effect of uniforming the wind speed distribution if the bent portion has a structure without fins. However, as shown in FIG. 10, since the evaporator second bent portion 5 is far from the axial fan 21, the wind speed is low, and the effect of uniforming the wind speed distribution by incorporating the present invention is relatively low. Therefore, in this embodiment, only the bent portion close to the axial flow fan 21 having a higher effect is configured without fins.

  As described above, even in a heat exchanger having bent portions at a plurality of locations, the wind speed distribution can be made uniform and the performance with respect to cost can be improved by making all or some of the bent portions have a structure without fins.

  The effects of the present invention are summarized below.

  According to the present invention, in the bent portion of the heat exchanger composed of a plurality of rows, by arranging a row in which the fin does not exist in the bent portion, the ventilation resistance of the bent portion is reduced without increasing the type of the fin, The cost performance is improved by the uniform wind speed distribution.

  Moreover, in the heat exchanger in which a plurality of bent portions exist, only the bent portion close to the air blower is configured to have no fins, thereby efficiently achieving uniform wind speed distribution.

  Moreover, by making the bent part on the most downstream side of the air into a row in which no fins are present, a decrease in the heat transfer area due to the elimination of the fins is suppressed, and the performance with respect to cost is further increased.

  Moreover, the fin flow efficiency of an adjacent row | line improves by making the refrigerant flow path of the part which does not exist a fin contact the fin of an adjacent row | line, and the performance with respect to cost increases more.

  Furthermore, by applying the heat exchanger of the present invention to an evaporator of a heat pump type heating device that heats cold water to warm water with a refrigerant or an outdoor heat exchanger of an air conditioner, with a limited product size and cost, Products with high energy savings can be provided.

The above embodiment is applied to a refrigeration cycle using CO ₂ as a refrigerant. However, since the effect does not change depending on the type of refrigerant, the apparatus using other refrigerants such as R32 and R410A can also be used. Applicable. Furthermore, the heat exchanger of Example 1 thru | or Example 3 was comprised with not only the heat pump water heater which has the structure which provided the axial flow fan in the outdoor unit, but the heat exchanger and the air blower, such as an air conditioner, for example. If it is a heat exchange system, an effect is acquired regardless of a product.

  In other words, a fin tube heat exchanger including a fin group in which plate-shaped fins are stacked and a plurality of fluid pipes penetrating the fin group, and heat exchange between air and fluid, and air between the fins. What is necessary is just a structure which is a heat exchanger unit provided with the ventilation fan distribute | circulated, Comprising: Fluid piping has a bending part and a part of bending part does not have a fin. The fluid flowing through the fluid piping may be water, brine, oil or other liquid, or air, nitrogen or other gas. Further, the fluid may be carbon dioxide or other refrigerant as described above.

  Further, as shown in the embodiments, the fluid piping may be a circular tube, or may have a rectangular, triangular, or hexagonal cross section.

  In the present specification, the refrigeration cycle apparatus includes a heat pump heating device, an air conditioner, a heat pump water heater, and the like.

  1: Evaporator rear surface, 2: Evaporator side surface, 3: Evaporator bent portion, 4: Evaporator second side surface, 5: Evaporator second bent portion, 6: Fin, 7: Fin plate portion, 8: Fin collar Part: 9: refrigerant pipe, 10: refrigerant inlet part, 11: refrigerant outlet part, 20: heat pump unit, 21: axial fan, 22: partition plate, 100: compressor, 101: water refrigerant heat exchanger, 102: Expansion valve, 103: Evaporator, 104: Hot water storage container, 105: Circulation pump for boiling, 106: Circulation pump for hot water supply, 107: Hot water supply heat exchanger, 108: Water pipe, 109: Hot water inlet, 200: Heat pump cycle, 201: Water side cycle, 202: Hot water supply cycle.

Claims (8)

A fin group heat exchanger that includes a fin group in which plate-shaped fins are stacked and a plurality of fluid pipes that penetrate the fin group, and performs heat exchange between air and fluid;
A blower for circulating the air between the fins,
The fluid pipe has a bent portion,
A part of the bent portion has a configuration that does not include the fins, thereby reducing the ventilation resistance of the bent portion.   The heat exchanger unit according to claim 1, wherein a portion having the smallest radius of curvature among the bent portions has a configuration in which the fins are not included. The blower is arranged to suck the air through the fin group,
The heat exchanger unit according to claim 1, wherein only the bent portion closest to the blower among the bent portions does not have the fins. The blower is arranged to suck the air through the fin group,
2. The heat exchanger unit according to claim 1, wherein only the bent portion located on the most downstream side of the air flow among the bent portions does not have the fins.   The heat exchanger unit according to claim 1, wherein the bent portion not having the fin is in contact with the fin group.   2. A configuration in which a plurality of fluid piping rows in which the plurality of fluid pipings are arranged so that respective central axes of the plurality of fluid pipings are positioned on a plane orthogonal to the air flow direction are stacked. The heat exchanger unit as described in any one of 1-5.   The heat exchanger unit according to any one of claims 1 to 6, wherein the blower is an axial fan. The fluid is a refrigerant;
The heat exchanger unit according to any one of claims 1 to 7, a compressor, an expansion valve, and another heat exchanger are connected in a ring shape to circulate the fluid. Refrigeration cycle equipment.

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