WO2013161038A1 - Heat exchanger and heat exchange method - Google Patents

Description

Heat exchanger and heat exchange method

The present invention relates to a heat exchanger and a heat exchange method.

There is a parallel flow type heat exchanger as one form of the heat exchanger. This heat exchanger includes a pair of header pipes and a plurality of flat tubes provided between the header pipes. After the fluid flowing into one header flows through the plurality of flat tubes, , Was configured to flow out to the other header pipe.

In such a parallel flow type heat exchanger, when a pair of header pipes are arranged vertically and vertically, the liquid refrigerant in the gas-liquid two-phase refrigerant flows into the flat tube located relatively below due to the influence of gravity. It became easy to flow, and it was difficult to distribute the refrigerant evenly through a plurality of flat tubes.

Therefore, in the configuration of the parallel flow type heat exchanger, there is also an aspect in which a pair of header pipes are arranged horizontally to make it less susceptible to gravity between a plurality of flat tubes.

On the other hand, in the existing outdoor unit of the air conditioner, there is a configuration in which the heat exchange surface is arranged on a plurality of surfaces of the casing of the outdoor unit. Here, when the parallel flow type heat exchanger in which the pair of header pipes described above are arranged horizontally is intended to function on a plurality of surfaces of the casing of the outdoor unit, each header pipe is bent along the plurality of surfaces. Must be. However, bending the header pipe into, for example, an L-shape or a U-shape has a problem that an excessive load is applied, the device is increased in size, and the cost is increased.

Regarding such a problem, there is one disclosed in Patent Document 1, for example. In the heat exchanger disclosed in Patent Document 1, a pair of header pipes are prepared separately for each of a plurality of surfaces.

JP 2010-107103 A

However, in the heat exchanger disclosed in Patent Document 1 described above, the refrigerant that has flowed through a plurality of flat tubes on one surface (first surface) is collected in a header pipe on the outflow side of the surface (first surface). After that, it is led to the header pipe on the inflow side of the next surface (second surface), and a plurality of flat tubes on the surface (second surface) are circulated. In addition, a mode leading to the next surface was adopted.

For this reason, there is an upstream / downstream relationship between a plurality of heat exchange function surfaces, and the heat exchange efficiency decreases as the surface on the downstream side. Moreover, since branching to a plurality of flat tubes and subsequent assembly are repeated, there is a possibility that the refrigerant after heat exchange cannot be suitably branched again to the plurality of flat tubes after the second surface.

The present invention has been made in view of the above, and while having a plurality of heat exchange function surfaces, it is possible to suppress the influence of gravity on the refrigerant and to suppress a decrease in heat exchange performance on each surface. It aims at providing the heat exchanger etc. which can do.

The heat exchanger of the present invention that achieves the above-described object has a plurality of heat exchange function surfaces, and each of the heat exchange function surfaces includes an upper header pipe, a lower header pipe, and a pair of upper and lower header pipes. The plurality of heat exchange function surfaces are in a parallel connection relationship, and the plurality of lower header pipes are connected to the lower collecting pipe via a flow dividing adjustment section.
Furthermore, the heat exchanging method of the present invention that achieves the same object is a heat exchanging method for exchanging heat on a plurality of surfaces, and in each of a plurality of heat exchanging function surfaces, an upper header pipe and a lower header pipe, Preparing a plurality of heat exchange pipes provided between a pair of header pipes, connecting the plurality of heat exchange function surfaces in parallel, and the plurality of lower header pipes are connected to a lower assembly via a flow dividing adjustment unit The refrigerant in the lower collecting pipe is diverted in parallel with the plurality of heat exchange function surfaces in the diversion adjusting unit, and heat exchange is performed on each of the plurality of heat exchange function surfaces, Outflow from the upper header pipe and join the upper collecting pipe.

According to the present invention, while having a plurality of heat exchange function surfaces, it is possible to suppress the influence of gravity on the refrigerant and to suppress a decrease in heat exchange performance on each surface.

It is a figure which shows the structure of the heat exchanger which concerns on Embodiment 1 of this invention. It is a perspective view of the lower header pipe for demonstrating a porous pipe. It is a figure which shows the liquid distribution characteristic of the lower header pipe as a comparative example. It is a figure which shows the liquid distribution characteristic of the lower pipe | tube with a built-in perforated pipe regarding this Embodiment 1. It is a figure which shows the external appearance and plane of a multi air-conditioner outdoor unit for buildings regarding Embodiment 1. FIG. It is a figure which shows the external appearance and plane of a package air conditioner outdoor unit regarding Embodiment 2. FIG.

Hereinafter, embodiments of a heat exchanger and a heat exchange method thereof according to the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a heat exchanger according to the first embodiment. The heat exchanger according to the present embodiment functions as an outdoor unit of an air conditioner that is installed in a target space and performs air conditioning. Therefore, when operating as a condenser during cooling, the refrigerant flows from top to bottom as shown by the dotted arrows in FIG. 1, and when operating as an evaporator during heating, the refrigerant is as shown in FIG. The parallel flow type heat exchanger flows from bottom to top as indicated by solid arrows in FIG.

The heat exchanger 1 has a plurality of heat exchange function surfaces 3. FIG. 1 shows an example in which there are three heat exchange function surfaces 3. Moreover, in the example of FIG. 1, it is comprised so that the adjacent heat exchange functional surface 3 may face the direction orthogonal.

Each of the heat exchange function surfaces 3 is provided with an upper header pipe 5, a lower header pipe 7, and a plurality of heat exchange pipes 9 provided between the pair of upper and lower header pipes 5, 7. Specifically, the heat exchange pipe 9 is a flat tube. Fins 11 (specifically corrugated fins) are provided between the heat exchange pipes 9.

One end of the upper communication pipe 13 is connected to each of the upper header pipes 5. The other end side of the upper connecting pipe 13 is connected to the upper collecting pipe 15. Each of the lower header pipes 7 is connected to a lower collecting pipe 19 via a flow dividing adjusting unit 17 described later. In this way, the plurality of heat exchange function surfaces 3 are arranged in parallel connection between the upper collecting pipe 15 and the lower collecting pipe 19. In addition, although illustration is abbreviate | omitted, between a pair of adjacent heat exchange function surfaces 3, it shall be covered with closing members, such as a metal plate, so that the fluid to be heat-exchanged may not bypass.

The diversion adjusting unit 17 adjusts the dryness and flow rate of the refrigerant supplied to the plurality of lower header pipes 7. As an example, the present embodiment supplies the gas-liquid two-phase refrigerant to the plurality of heat exchange function surfaces 3 at a uniform dryness and flow rate when the refrigerant flows from bottom to top during heating. The configuration will be described.

As an example of a configuration that realizes the equalization of the dryness and the flow rate, the diversion adjusting unit 17 includes a distributor 21 and at least one (two in the drawing) flow rate adjusting unit 23. One end side of the distributor 21 is connected to the lower collecting pipe 19, and a plurality of connection ports on the other end side are respectively connected to one end of the corresponding lower connecting pipe 25. Further, the other ends of the lower communication pipes 25 are respectively connected to the collecting side entrances 7 a of the corresponding lower header pipes 7. The distributor 21 connected in this way supplies the refrigerant with a uniform dryness to the plurality of lower communication pipes 25.

In the illustrated example, the flow rate adjusting unit 23 is a capillary tube. The flow rate adjusting unit 23 is provided between the distributor 21 and the corresponding lower header pipe 7, that is, in the lower communication pipe 25, but is not necessarily arranged in all the lower communication pipes 25.

In each of the heat exchange function surfaces 3, the collecting side inlet / outlet 7 a of the lower header pipe 7 and the collecting side inlet / outlet 5 a of the upper header pipe 5 are located in mutually opposite directions in the direction in which the header pipe extends. In other words, the gathering side entrance 7a of the lower header pipe 7 is provided on one end side of the lower header pipe 7, and the gathering side entrance 5a of the upper header pipe 5 is provided on the other end side of the upper header pipe 5. ing. That is, the refrigerant flow path between the collecting side inlet / outlet 5a and the collecting side inlet / outlet 7a is designed so that the flow path lengths are substantially equal regardless of which heat exchange pipe 9 is passed through.

As shown in FIG. 2, a porous tube 27 is provided inside each of the lower header pipes 7. FIG. 2 is a perspective view of the lower header pipe for explaining the perforated pipe. A plurality of heat exchange pipes 9 to be above the lower header pipe 7 and communication holes with the heat exchange pipes 9 are not shown. Yes.

The perforated pipe 27 is a block-like or pipe-like member, and is provided in a state of being floated from the inner surface of the lower header pipe 7 around the center of the space in the lower header pipe 7. The porous tube 27 is provided with a number of distribution holes 29. As an example, the distribution hole 29 is disposed substantially below the perforated tube 27.

A double pipe structure is obtained by combining the perforated pipe 27 and the lower header pipe 7. Thus, for example, during heating, the refrigerant flowing through the lower connecting pipe 25 once flows into the porous pipe 27, and then equally from the multiple distribution holes 29 in the depth direction (left and right direction in FIG. 2), It flows out of the perforated pipe 27, is further uniformly distributed in the lower header pipe 7, and is evenly supplied to the plurality of heat exchange pipes 9 from communication holes (not shown) on the upper surface of the lower header pipe 7.

Next, the effect of the porous tube described above will be described. FIG. 3 is a diagram showing the liquid distribution characteristics of a lower header pipe as a comparative example which is horizontally arranged and does not have a porous tube inside, and FIG. 4 is a lower portion of a porous tube built-in type according to the present embodiment which is horizontally arranged. It is a figure which shows the liquid distribution characteristic of a header pipe.

Also, the graphs in FIGS. 3 and 4 have a path No. on the horizontal axis. That is, the flow number of the heat exchange pipes arranged in the depth direction of the lower header pipe (the flow paths of the 28 flat tubes inserted perpendicularly to the upper surface of the lower header pipe) is shown. The liquid distribution ratio for each is shown. In addition, experimental results of three cases 1, 2, and 3 in which the refrigerant flow rate Gr [kg / hour] and the inlet dryness X are changed are shown for each of the comparative example and the lower header pipe of the present embodiment.

First, in the comparative example shown in FIG. 3, in cases 1 and 3 where the refrigerant flow rate Gr is 90 [kg / hour] and the inlet dryness X is different, the refrigerant rebounds while remaining in the lower header pipe 7 ′. It can be seen that the liquid flows out to the heat exchange pipe 9 as it is, and therefore the liquid distribution ratio increases in the downstream area (path Nos. 23 to 28). Further, in case 2 with a flow rate of 180 [kg / hour] larger than cases 1 and 3, due to the presence of abundantly supplied liquid refrigerant, the effect of rebounding at the back of the lower header pipe 7 'and the effect of disturbing the flow, the liquid deviation characteristics Tend to be relaxed to some extent. However, it can be seen that any case is deviated from the example of the equal wiring shown in parallel with the horizontal axis.

On the other hand, in the lower header pipe with a built-in perforated pipe according to the present embodiment shown in FIG. 4, the three cases 1, 2, and 3 are good substantially along the wiring evenly regardless of the refrigerant flow rate and the inlet dryness. It can be seen that excellent liquid distribution characteristics are obtained. This is because the porous tube 27 is inserted into the lower header pipe 7 and the distribution hole 29 is disposed downwardly of the porous tube 27 so that the inner surface of the lower header pipe 7 and the outer surface of the porous tube 27 are surrounded. The action of stirring the liquid film of the refrigerant in the annular region by the bubbles ejected from the bottom of the perforated tube 27 is obtained as desired regardless of the dryness of the inlet and the flow rate. Even distribution is realized.

Subsequently, a specific application example of the heat exchanger shown in FIG. 1 will be described. Although this Embodiment illustrated the aspect which adjusts a refrigerant | coolant dryness and a refrigerant | coolant flow rate equally with respect to the several heat exchange functional surface 3, as a concrete application example, it is to the multi air conditioner outdoor unit for buildings. The application of FIG. 5 is a diagram illustrating an appearance and a plan view of a multi-air conditioner outdoor unit for buildings. Multi-air conditioner outdoor units for buildings are larger than those for general households and are used as high-processing devices.

As shown in FIG. 5, the building multi-air conditioner outdoor unit 101 has the heat exchange function surface 3 assigned to each of the three surfaces of the housing 103, and the propeller fan 105 is arranged in the center in plan view. Yes. Then, air is sucked into the housing 103 as indicated by an arrow 107 from each of the three side surfaces of the housing 103, and heat is exchanged by each heat exchange function surface 3, and a fan provided on the upper surface of the housing 103. From the air outlet formed in the guard 109, it discharges as shown by the arrow 111 (top flow type).

Next, the operation of the heat exchanger and the heat exchange method according to the present embodiment configured as described above will be described. During the heating operation, the heat exchanger 1 that is an outdoor unit operates as an evaporator, and the gas-liquid two-phase refrigerant that has entered the distributor 21 becomes a homogeneous spray flow when passing through an orifice (not shown). The flow rate is adjusted by each flow rate adjusting unit 23 and flows into the lower header pipe 7 of the corresponding heat exchange function surface 3. The refrigerant flowing in from the collecting side inlet / outlet 7 a of the lower header pipe 7 is ejected from the distribution hole 29 of the perforated pipe 27 and is evenly distributed to the heat exchange pipes 9. In the perforated tube 27, when the dryness is large, minute droplets are ejected from the small holes, and when the dryness is small, the bubbles are ejected to the liquid portion accumulated in the annular portion. Distribution is realized. The refrigerant exchanges heat with air (not shown) when passing through each heat exchange pipe 9, and then flows into the upper header pipe 5 from the collection side entrance / exit 5 a that is opposite to the collection side entrance / exit 7 a of the lower header pipe 7. leak. The refrigerant flowing out from each collecting side entrance / exit 5a passes through the corresponding upper connecting pipe 13 and joins in the upper collecting pipe 15. During the cooling operation, the heat exchanger 1 operates as a condenser and the refrigerant flow is reversed.

As described above, according to the heat exchanger of the present invention and the heat exchange method using the heat exchanger, the following advantages are obtained. First, in each of the heat exchange function surfaces, the header pipes are oriented horizontally, so that the influence of gravity on the refrigerant flow can be suppressed, and the refrigerant can be evenly distributed to a plurality of heat exchange pipes. it can. Furthermore, while the header pipes are horizontally arranged in such a manner, it is possible to exert a heat exchange function on a plurality of surfaces without being hindered by the fact that it is difficult to form a curved header pipe. . Furthermore, while heat exchange is performed on each of the plurality of surfaces, the refrigerant flow is divided in parallel with respect to the plurality of heat exchange function surfaces. There is no downstream relationship, and good heat exchange efficiency can be maintained in each of the heat exchange function surfaces. In particular, in the present embodiment, the refrigerant dryness and flow rate are adjusted as desired according to the conditions of each heat exchange function surface via the distributor and the flow rate adjustment unit, and then distributed and supplied to the heat exchange function surface. In all heat exchange functions, extremely good heat exchange performance can be obtained. In addition, since the refrigerant that has exchanged heat once with a plurality of heat exchange pipes is collected in the heat exchanger as a whole and does not have a flow path that is again divided into the plurality of heat exchange pipes, There is no problem that the refrigerant cannot be evenly supplied to the exchange pipe. Thus, according to the heat exchanger and the heat exchange method according to the present embodiment, the influence of gravity on the refrigerant can be suppressed and the heat on each surface can be suppressed while having a plurality of heat exchange function surfaces. It is possible to suppress a decrease in exchange performance.

Moreover, in each heat exchange function surface, since the entrance and exit of the lower header pipe and the entrance and exit of the upper header pipe are arranged on the opposite side, the refrigerant has almost the same pressure loss regardless of the heat exchange pipe, That is, uniform distribution of the gas-liquid two-phase flow can be realized. In addition, by providing a perforated tube in the lower header pipe, fine droplets and bubbles are ejected from the distribution holes to the annular structure of the double structure, which also promotes uniform distribution of the gas-liquid two-phase refrigerant Is done. Further, in the present embodiment, the number of distribution to the heat exchange pipe is increased and the number of distribution is kept low (in the above example, the number of distribution is limited to one time), so that a very large number of heat exchange functional surfaces are prepared. Although the heat exchange pipe is used, the refrigerant pressure loss can be kept low for the number of heat exchange pipes. Therefore, in particular, a low-pressure refrigerant (such as a refrigerant having a large refrigerant pressure loss) such as HFO1234yf, HFO1234ze, or R134a can be effectively used.

Embodiment 2. FIG.
A second embodiment of the present invention will be described with reference to FIG. In the said Embodiment 1, according to the heat load (it mainly depends on the passing wind speed of a heat exchange part) which adjusts a refrigerant | coolant dryness equally with respect to several heat exchange function surface, and is different in each heat exchange function surface. Although the aspect which changes a refrigerant | coolant flow volume was illustrated, this invention is not limited to this. That is, the present invention includes an aspect in which the refrigerant dryness and / or the refrigerant flow rate are adjusted to be different in a plurality of heat exchange function surfaces. A specific application example is application to a packaged air conditioner outdoor unit. FIG. 6 is a diagram illustrating an appearance and a plane of the packaged air conditioner outdoor unit.

As shown in FIG. 6, in the packaged air conditioner outdoor unit 201, the heat exchange function surface 3 is assigned to each of the side surface and the back surface of the housing 203. By rotation of the propeller fan 205, air is sucked into the housing 203 as indicated by an arrow 207 from each of the side surface and the back surface of the housing 203, and heat is exchanged at each heat exchange function surface 3, and the front surface of the housing 203 As shown by the arrow 211, it discharges from the blower outlet provided in.

Even in this second embodiment, as in the first embodiment, while having a plurality of heat exchange function surfaces, the influence of gravity on the refrigerant can be suppressed and the heat exchange performance on each surface is degraded. Can be suppressed.

Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical idea and teachings of the present invention. It is self-explanatory.

For example, in the above-described perforated pipe, it has been described that there are a large number of distribution holes facing downward. However, the distribution hole formation mode is not limited to this, and the orientation, number, and shape of the distribution holes are appropriately changed. Is possible. The above-described configuration of the flow dividing adjustment unit is merely an example, and can be modified as appropriate. For example, the height position of multiple outlet side branch paths such as Y-shaped branch pipes and low-pressure loss distributors are made different from each other, the ratio of the liquid phase diversion is changed by the influence of gravity, and the dryness and flow rate are adjusted simultaneously. It is also possible to use the diversion adjusting unit of the aspect.

1 heat exchanger, 3 heat exchange function surface, 5 upper header pipe, 7 lower header pipe, 5a, 7a collecting side entrance, 9 heat exchanging pipe, 17 shunt adjusting section, 19 lower collecting pipe, 21 distributor, 23 flow rate adjusting section , 25 lower connecting pipe, 27 perforated pipe, 29 distribution holes.

Claims (7)

It has multiple heat exchange functions
In each of the heat exchange functional surfaces, it has an upper header pipe and a lower header pipe, and a plurality of heat exchange pipes provided between the pair of upper and lower header pipes,
The plurality of heat exchange function surfaces are in a parallel connection relationship,
The plurality of lower header pipes are connected to the lower collecting pipe via the flow dividing adjustment section,
Heat exchanger. The shunt adjusting unit includes a distributor and at least one flow rate adjusting unit,
The distributor is provided between the lower collecting pipe and the plurality of lower header pipes, and equalizes the dryness of the refrigerant supplied to the plurality of lower header pipes,
The at least one flow rate adjusting portion is disposed between the distributor and the corresponding lower header pipe;
The heat exchanger according to claim 1. The heat exchanger according to claim 1 or 2, wherein each of the plurality of lower header pipes has a porous tube therein. In each of the heat exchange functional surfaces, the lower header pipe collecting side entrance is provided on one end side of the lower header pipe, and the upper header pipe collecting side entrance is on the other end side of the upper header pipe. The heat exchanger according to any one of claims 1 to 3, wherein the heat exchanger is provided. The heat exchanger according to any one of claims 1 to 4, wherein the low-pressure refrigerant is HFO1234yf, HFO1234ze, or R134a. A heat exchange method for exchanging heat on a plurality of surfaces,
In each of the plurality of heat exchange function surfaces, an upper header pipe and a lower header pipe, and a plurality of heat exchange pipes provided between the pair of upper and lower header pipes are prepared,
The plurality of heat exchange function surfaces are connected in parallel, and the plurality of lower header pipes are connected to the lower collecting pipe via a flow dividing adjustment unit,
The refrigerant in the lower collecting pipe is diverted in parallel to the plurality of heat exchange function surfaces in the diversion adjusting unit, heat exchange is performed in each of the plurality of heat exchange function surfaces, and the refrigerant flows out of the plurality of upper header pipes Let it join the upper collecting pipe,
Heat exchange method. The heat exchange method according to claim 7, wherein the low-pressure refrigerant is HFO1234yf, HFO1234ze, or R134a.

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