JP2019045063A - Heat exchanger - Google Patents

Abstract

To improve a split flow balance under a condensation condition, in a heat exchanger that has the large number of refrigerant flow passages and a small hole diameter of the flow passage.SOLUTION: When a heat exchanger 1 functions as a condenser, an inner diameter of a header a6 on a side of a heat exchanger inlet/outlet a4 to be a condenser inlet is reduced to increase a refrigerant flow velocity on a side of the condenser inlet and an influence degree of the refrigerant flow velocity on the side of the condenser inlet relative to a refrigerant split flow is enhanced, whereby refrigerant reaches downstream of an inside of the header a6; thus, a split flow of the heat exchanger 1 is improved.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plate stack type heat exchanger

  In general, a heat exchanger used in a home air conditioner exchanges heat between air and a refrigerant flowing inside the heat exchanger to perform air conditioning in a room. In order to improve the performance of this type of heat exchanger, it is possible to increase the heat transfer area outside the heat transfer tubes, fins and heat transfer tubes, to reduce the resistance of air passing outside the heat exchanger, and to flow through the heat exchanger. It is effective to reduce the pressure loss of

  As a means for reducing the pressure loss of the refrigerant, it comprises a fin group into which air flows in, a heat transfer pipe group inserted in the fin group and the refrigerant flowing inside, and a header connecting the ends of the heat transfer pipe group. In the heat exchanger, there is proposed a means for dividing the header, providing a connecting pipe for connecting the divided header pipes, and making the diameter of one of the divided headers larger than the diameter of the other header. (See, for example, Patent Document 1).

  Under the evaporation condition, the gas-liquid two-phase refrigerant has more gas components as it goes downstream, the flow velocity increases, and the pressure loss on the refrigerant side increases. Therefore, the above prior art reduces the increase in pressure loss of the refrigerant by making the header diameter on the evaporator outlet side larger than the header diameter on the evaporator inlet side and reducing the refrigerant flow rate on the evaporator outlet side. . In addition, the refrigerant flows into the heat exchanger as a gas refrigerant under condensation conditions, but the flow direction of the refrigerant is opposite to that under evaporation conditions, so the header diameter on the condenser inlet side with many gas components becomes large, Since the flow rate of refrigerant on the inlet side of the condenser decreases, it is possible to reduce the pressure loss on the refrigerant side even under condensation conditions.

JP-A-4-268128

  However, if the number of refrigerant channels is very large, as in a flat tube or plate-stacked heat exchanger, if the header on the condenser inlet side has a large diameter and the refrigerant flow velocity in the header is small under condensation conditions, the refrigerant The amount of refrigerant that flows from the refrigerant flow path closer to the header upstream side, that is, the inlet side sequentially, flows to the refrigerant flow path farther from the header downstream side, that is, the refrigerant flow path farther from the inlet side decreases. There is a problem that the concentration is concentrated, and the amount of heat exchange between the air and the refrigerant is reduced.

  In order to solve the above-mentioned conventional problems, the heat exchanger according to the present invention flows a second fluid between a plate fin laminate having a flow path through which a first fluid flows, and each layer of the plate fin laminate, A heat exchanger for exchanging heat between a first fluid and the second fluid, wherein the plate fin laminate is connected to the inlet and the outlet of the flow passage, and the first fluid flows. A header pipe and a second header pipe are provided, and the inner diameter of the first header pipe which is a condenser inlet under the condition where the first fluid condenses is equal to the inner diameter of the second header pipe which is a condenser outlet. Too small.

  With such a configuration, the refrigerant can flow evenly to each layer of the plate fin laminate of the heat exchanger, and the performance deterioration of the heat exchanger can be suppressed.

  The heat exchanger of the present invention facilitates the flow of the refrigerant that easily flows to the layer of the plate fin laminate on the upstream side of the header into the layer of the plate fin laminated on the downstream side of the header, and can evenly distribute the refrigerant to the layers. It is possible to suppress a decrease in the heat exchange capacity of the heat exchanger as a whole.

The perspective view of the heat exchanger in Embodiment 1 of this invention Front view of plate fins in Embodiment 1 of the present invention Front view of plate fins in Embodiment 1 of the present invention Front view of plate fins in Embodiment 1 of the present invention Front view of plate fins in Embodiment 1 of the present invention Channel cross-sectional view at the time of plate lamination in Embodiment 1 of the present invention The figure which showed the flow of air and a refrigerant | coolant at the time of condensing conditions in Embodiment 1 of this invention The figure which showed the flow of air and a refrigerant | coolant at the time of evaporation conditions in Embodiment 1 of this invention. Simplified diagram showing the effect of the present invention Simplified diagram showing prior art

According to a first aspect of the present invention, a second fluid is flowed between a plate fin laminate having a flow path through which the first fluid flows, and each layer of the plate fin laminate, and the first fluid and the second fluid are flowed. A heat exchanger for exchanging heat, wherein the plate fin laminate is provided with a first header pipe and a second header pipe which are connected to the inlet and the outlet of the flow path and through which the first fluid flows. The inner diameter of the first header pipe, which is the inlet of the condenser under the condition that the first fluid condenses, is smaller than the inner diameter of the second header pipe, which is the outlet of the condenser.
According to this configuration, in the heat exchanger having minute and very many refrigerant flow paths, the refrigerant can be distributed to the entire heat exchanger under condensing conditions.

According to a second invention, in the first invention, a flow dividing control pipe for controlling a refrigerant flow of each of the plate fin laminates is inserted into the first header pipe.
With this configuration, the influence of the pressure loss at the evaporator outlet side on the refrigerant split of the entire heat exchanger is enhanced under evaporation conditions, and the size and the pitch of the holes provided in the longitudinal direction of the split control pipe are adjusted. It is easy to control the refrigerant diversion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited by the embodiments.

Embodiment 1
FIG. 1 is a perspective view of the heat exchanger in the first embodiment.

  In FIG. 1, the heat exchanger 1 is configured by laminating a plurality of plate fins 51, 52, 53, 54, and is provided with an end plate a2 and an end plate b3 at both ends. The end plate a2 is provided with a heat exchanger inlet / outlet a4 through which the refrigerant flows in and out, and a heat exchanger inlet / outlet b5.

  2, 3, 4 and 5 are front views of plate fins 51, 52, 53, 54 used in the heat exchanger 1 in the first embodiment.

In FIG. 2, the plate fin a51 has a header a6 with a small inside diameter on the heat exchanger inlet / outlet a4 side and a header b7 with a large inside diameter on the heat exchanger inlet / outlet port b5 side.
A plurality of refrigerant channels 8 are provided between them. In addition, it has a manifold a9, a manifold b10, and a manifold c11 in which the refrigerant is branched and merged. In the condensation condition, the header 6 is on the condenser inlet side, the header 7 is on the condenser outlet side, and in the evaporation condition, the refrigerant flow direction is reverse, so the heat exchanger inlet / outlet a4 is the evaporator outlet, heat exchange The inlet / outlet port b5 is the evaporator inlet.

  The plate fin b52 of FIG. 3 is paired with the plate fin a51, and the plate fin c53 of FIG. 4 and the plate fin d54 of FIG. 5 are paired.

  FIG. 6 shows a cross-sectional view of a state in which a plurality of plate fins 2 in Embodiment 1 are stacked.

  In FIG. 6, the plate fins 51 and the plate fins 52 are put together, the plate fins 53 and the plate fins 54 are put together, and the refrigerant flow path 8 is configured respectively. The plate fins 51 and the plate fins 52, the plate fins 53 and the plate fins 54 are alternately stacked to form the air flow path 12, and the air 13 flows between the plate fins 51, 52, 53, 54.

  FIG. 7 illustrates the flow of air and refrigerant under condensing conditions.

  In FIG. 7, the air 13 flows into the heat exchanger from the heat exchanger inlet / outlet port b5 side of the plate fin 53 and flows out to the inlet / outlet port a4 side, and exchanges heat with the refrigerant 14 flowing in the refrigerant channel 8 during this time. On the other hand, the refrigerant 14 which has flowed in from the heat exchanger inlet / outlet a4 has many gas components and is divided into six refrigerant flow paths 8 from the manifold a9 while flowing in the axial direction of the header a6. When it joins to the manifold c11 and flows out to the heat exchanger inlet / outlet b5 from the axial direction of the header 7b, it is a liquid single phase refrigerant. In the present embodiment, although six refrigerant channels 9 on the heat exchanger inlet / outlet side a4 and two refrigerant channels 8 on the heat exchanger inlet / outlet port b5 side, any number of refrigerant channels may be used.

  FIG. 8 illustrates the flows of air and refrigerant under evaporation conditions.

  In the evaporation condition and the condensation condition, the flow of the refrigerant 14 is in the opposite direction, and the flow of the air 13 is the same as that in the condensation condition. Under the evaporation condition, the refrigerant flowing from the heat exchanger inlet / outlet b5 is in a gas-liquid two-phase state in which gas and liquid are mixed, and while flowing through the refrigerant flow path 8, exchanges heat with air, and from the heat exchanger inlet / outlet a4 When it flows out, it has become a state with many gas components.

  FIGS. 9 and 10 are simplified diagrams for explaining the effects of the present invention and the prior art, and FIG. 9 is the one in which the inner diameter of the condenser inlet header is reduced similarly to the present invention, and FIG. The header inner diameter on the inlet side of the condenser is increased.

The heat exchanger 21 of FIG. 10 has a header a22 having a large inner diameter at the condenser inlet 24 and a header d23 having a smaller inner diameter than the header c22 at the condenser outlet 25. A plurality of refrigerants are provided between the header 22c and the header 23d. The flow path 26 is joined. Assuming that the flow rate of the refrigerant flowing into the heat exchanger is Q, and the number of the plurality of refrigerant flow paths is n, the refrigerant flow rate Q flowing into the heat exchanger is the number n of refrigerant flow paths in all the refrigerant flow paths. Ideally, the divided Q / n refrigerant flow should flow evenly. However, the refrigerant flow at the time of condensation is affected by the flow rate of the refrigerant flowing into the heat exchanger, the flow velocity in the header, the pressure loss in the refrigerant flow path in the header and in the header, and the refrigerant is distributed equally to all the refrigerant flow paths. It is difficult to do. Particularly in the configuration as shown in FIG. 10, since the inner diameter of the header c22 is large and the flow velocity of the refrigerant is small, the influence of pressure loss in the refrigerant branch increases, and the pressure loss of the pressure loss is close to the condenser inlet 24 and the condenser outlet 25 The refrigerant 27 easily flows in the refrigerant flow passage 26 on the upstream side of the small header c22. As a result, the refrigerant 2 flowing in the refrigerant channel 26 on the downstream side of the header c 22
The shortage of 7 will reduce the condensation capacity.

  Therefore, as shown in FIG. 9, the heat exchanger 31 includes the header e32 in which the inner diameter on the condenser inlet 34 side is reduced, and increases the refrigerant flow rate on the condenser inlet 34 side. When the influence of the flow velocity in the inlet side header in the refrigerant diversion increases, the refrigerant easily flows in the longitudinal direction of the header e32, and the refrigerant 37 can be evenly distributed on the downstream side of the header e32, and the condenser capacity can be increased.

  Table 1 is a heat exchanger according to the embodiment, in which the inner diameter of the header on the inlet side of the condenser is φ 9.5 mm, and the condensation capacity of φ 6.0 mm is compared, assuming that the capacity of φ 9.5 mm is 100%. The φ 6.0 mm capacity is 103%. Thus, if the header diameter on the condensation inlet side is smaller than the header diameter on the condenser outlet side, the refrigerant can be distributed to the downstream side of the header, and the condenser capacity increases.

  In the evaporator condition, the flow is reverse to that in the condensation condition, the condenser inlet 34 is the evaporator outlet, and the condenser outlet 35 is the evaporator inlet. It is necessary to carry out at the evaporator inlet or the evaporator outlet to control the refrigerant distribution of the entire heat exchanger under evaporation conditions, but the refrigerant flowing from the evaporator inlet is a mixture of gas and liquid There are many parameters that affect the refrigerant diversion, such as the gas-liquid two-phase state, the ratio of gas to liquid, the refrigerant flow velocity, the flow mode, and the pressure loss of the header and the refrigerant flow path. In the present invention, since the inner diameter of the header e32 is small on the evaporator outlet side where the refrigerant is in the gas single phase, the refrigerant pressure loss generated on the evaporator outlet side can be increased, and the degree of influence on the refrigerant distribution can be increased. And, by inserting the branch control pipe on the evaporator outlet side and adjusting the size and the pitch of the holes provided in the longitudinal direction of the branch control pipe, it is possible to easily control the refrigerant branch on the evaporator outlet side.

  In the embodiment of the present invention, the heat exchanger is a plate laminated type heat exchanger, but it may be a parallel flow heat exchanger using a flat weir joined to two headers.

  According to the present invention, in a heat exchanger having a small number and a large number of refrigerant flow paths joined to two headers, a refrigerant flow can be improved under condensing conditions, so a heat exchanger with high performance can be provided. For this reason, the heat exchanger of the present invention can be applied not only to household air conditioners but also to vehicle air conditioners for business use.

1 heat exchanger 2 end plate a
3 end plate b
4 heat exchanger entrance a
5 heat exchanger entrance b
6 header a
7 header b
8 Refrigerant channels 9 manifold a
10 Manifold b
11 manifold c
12 air flow path 13 air 14 refrigerant 21 heat exchanger 22 header c
23 header d
24 condenser inlet 25 condenser outlet 26 refrigerant flow path 27 refrigerant 31 heat exchanger 32 header e
33 header f
34 condenser inlet 35 condenser outlet 36 refrigerant flow channel 37 refrigerant 51 plate fin a
52 plate fins b
53 plate fin c
54 plate fin d

Claims (2)

A plate-fin stack having a flow path through which a first fluid flows, and a heat exchanger that flows a second fluid between the layers of the plate-fin stack and exchanges heat between the first fluid and the second fluid. A first header pipe and a second header pipe connected to the inlet and the outlet of the flow path and through which the first fluid flows are installed in the plate fin laminate; A heat exchanger characterized in that the inner diameter of a first header pipe which is a condenser inlet under the condition that A condenses is smaller than the inner diameter of a second header pipe which is a condenser outlet.   The heat exchanger according to claim 1, wherein a flow control pipe for controlling a refrigerant flow of each of the plate fin laminates is inserted inside the first header pipe.

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