JPH06257892A - Parallel flow heat exchanger for heat pump - Google Patents

Abstract

(57) [Summary] [Objective] When the parallel flow heat exchanger is applied as a heat exchanger for a heat pump, optimal refrigerant distribution is obtained both as a condenser and as an evaporator. [Structure] Upper header pipe 1b horizontally arranged at the top
And the upper header pipe 1b below the upper header pipe 1b.
Lower header pipe 1a arranged in parallel with each other, a plurality of perforated flat branch pipes 2 vertically connecting the two, and corrugated fins 3 arranged so as to meander between the perforated flat branch pipes.
And the lower header pipe 1a and the upper header pipe 1b are connected to the refrigerant inlet / outlet ports 5 and 6, respectively. When this heat exchanger is used as an evaporator, the refrigerant inlet / outlet 5 is a liquid refrigerant inlet, the refrigerant inlet / outlet 6 is a refrigerant vapor outlet, and when it is used as a condenser, the refrigerant inlet / outlet 6 is a refrigerant vapor inlet and the refrigerant outlet / inlet 5 is a liquid refrigerant outlet. Use as a refrigerant outlet. [Effect] The distribution of the refrigerant between the perforated flat branch pipes is almost uniform, and the invention can be applied to both a condenser of a heat pump and an evaporator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to heat exchangers for heat pumps such as room air conditioners and package air conditioners, which are applicable to both indoor heat exchangers and outdoor heat exchangers, and particularly used as evaporators. It is targeted at parallel flow heat exchangers that provide good refrigerant distribution both when used as a condenser and when used as a condenser.

[0002]

2. Description of the Related Art A heat exchanger called a parallel flow type in which porous flat branch pipes and corrugated fins are laminated and both ends of each flat branch pipe are connected to a pair of hollow header pipes is disclosed in Japanese Patent Publication No. 3-45300. Although there are many publicly known examples including Japanese Patent Publication No. JP-A-2003-264, since all of them are intended for condensers, the header pipe stands vertically to the left and right without water drops or frost on the fins. Recently, an attempt was made to use this parallel flow condenser as an indoor heat exchanger of a room air conditioner, and as shown in Japanese Patent Laid-Open No. 4-131665,
Since it is used as an evaporator, removal of water droplets on the fin surface becomes a problem, and header pipes are arranged above and below. However, this known example is not devised from the viewpoint of being used not only as an evaporator for a heat pump but also as a condenser.

On the other hand, as for the cross fin tube type heat exchanger which has been conventionally used for a heat pump, as shown in Japanese Patent Application Laid-Open No. 4-24493, it can be used also as a condenser.
Although consideration has been given to uniform distribution of the refrigerant also in the evaporator, it cannot be applied to the parallel flow heat exchanger as it is because the shape of the refrigerant heat transfer tube is different.

[0004]

When the condenser disclosed in Japanese Examined Patent Publication No. 3-45300 is used as it is as a heat exchanger for a heat pump, water droplets attached to the fin surface when used as an evaporator There is a problem that it is difficult to remove the refrigerant and the refrigerant is evenly distributed, so that the sufficient capacity cannot be exhibited.

Further, Japanese Patent Laid-Open No. 4-1 devised as an evaporator
As shown in Japanese Patent No. 31665, there is an example in which head pipes are horizontally arranged vertically to improve the removal of water droplets.
No consideration is given to refrigerant distribution as a condenser.

Therefore, the problem to be solved by the present invention is that when the parallel flow heat exchanger is applied to a heat pump, an appropriate refrigerant distribution can be obtained both as a condenser and as an evaporator, and a sufficient heat exchange amount can be obtained. Is to obtain a parallel flow heat exchanger.

[0007]

The present invention employs the following technical means in order to achieve the above items. That is,
In a parallel flow heat exchanger in which two header pipes are horizontally arranged above and below and a plurality of perforated flat branch pipes connect between them in the vertical direction, a refrigerant inlet / outlet is provided in each of the upper header pipe and the lower header pipe, When the heat exchanger is used as an evaporator, the refrigerant inlet / outlet of the lower header pipe is used as the liquid refrigerant inlet, the refrigerant inlet / outlet of the upper header pipe is used as the refrigerant vapor outlet, and when used as a condenser, the refrigerant inlet / outlet of the upper header pipe is used. Is used as the refrigerant vapor inlet, and the refrigerant inlet / outlet of the lower header pipe is used as the liquid refrigerant outlet. Each refrigerant inlet / outlet may be mounted perpendicularly to the axis of the header pipe, or may be mounted parallel to the header (in the direction in which the header is extended).

In order to achieve the above object, the present invention also provides:
In a parallel flow heat exchanger in which two header pipes are horizontally arranged above and below, and a plurality of perforated flat branch pipes connect between them in the vertical direction, a refrigerant inlet / outlet is provided in each header pipe, and the refrigerant inlet / outlet is It is characterized in that it is attached perpendicularly to the flow of the refrigerant in the header and also perpendicularly to the flow of the refrigerant in the perforated flat branch pipe.

In order to achieve the above object, the present invention also provides
In a parallel flow heat exchanger in which two header pipes are arranged horizontally at the top and bottom and are vertically connected by a plurality of perforated flat branch pipes, at least two refrigerant inlets and outlets are provided in each header pipe. Installed vertically to the flow of the refrigerant inside, and perpendicular to the flow of the refrigerant inside the perforated flat branch pipe, the number of refrigerant inlets and outlets provided in the upper header pipe and the number of refrigerant inlets and outlets provided in the lower header pipe are the same, and the same porous It is characterized in that a refrigerant inlet / outlet is provided near both ends of the flat branch pipe. In this case, it is desirable that the refrigerant inlet / outlet pipes are provided at substantially the same intervals so that one refrigerant inlet / outlet pipe corresponds to substantially the same number of perforated flat branch pipes.

[0010]

When the heat exchanger according to the present invention is used as an evaporator, the refrigerant inlet / outlet provided in the lower header is used as a liquid refrigerant inlet, and the refrigerant inlet / outlet provided in the upper header is used as a refrigerant vapor outlet. Therefore, the refrigerant changes from liquid to vapor and rises as the density decreases, and the flow is smooth. When the heat exchanger according to the present invention is used as a condenser, the refrigerant inlet / outlet provided in the upper header pipe is used as a refrigerant vapor inlet, and the refrigerant inlet / outlet provided in the lower header pipe serves as a liquid refrigerant outlet. Changes from vapor to liquid and descends as the density increases, and the flow of the refrigerant is smooth. Furthermore, since the porous flat branch pipes are arranged vertically, water droplets adhering to the fin surface are easily washed out naturally when acting as an evaporator, and the ventilation resistance when wet can be suppressed to a low level.

Further, when the refrigerant inlet / outlet is vertically attached to the refrigerant flow in the header and the refrigerant flow in the perforated flat branch pipe, the operating energy of the refrigerant in the refrigerant inlet / outlet directly affects the refrigerant distribution. Never give. The speed of the refrigerant in the refrigerant inlet / outlet collides with the wall of the header and becomes static pressure before flowing through the header. Therefore, the flow in the header becomes gentle and is easily uniformized. As a result, the refrigerant distribution is improved. Further, since the direction of the refrigerant inlet / outlet is also perpendicular to the direction of the refrigerant flow in the perforated flat branch pipe, the refrigerant velocity at the refrigerant inlet / outlet does not directly affect the flow in the perforated flat branch pipe.

Furthermore, since the number of refrigerant inlet / outlet ports provided in the upper header pipe and the number of refrigerant inlet / outlet ports provided in the lower header pipe are made to coincide with each other and the positions thereof are opposed to each other, the static pressure distribution in the header is distributed. However, the upper and lower headers have almost the same shape. This state is shown in FIG. In the lower header pipe, where the static pressure is low, the static pressure is also low in the upper header pipe, and the static pressure difference between the upper and lower headers is
The value is almost constant at any position of the porous flat branch pipe. Therefore, the distribution of the refrigerant becomes uniform, and a sufficient amount of heat for exchange can be obtained.

[0013]

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

FIG. 5 is a perspective view of a conventional parallel flow heat exchanger. Since it is used as a condenser, superheated refrigerant vapor enters the left header 1 from the refrigerant inlet 6.
It is distributed to a large number of perforated flat branch pipes 2 arranged horizontally,
It is cooled by the air flow 7 passing between the corrugated fins 3. The refrigerant vapor in the perforated flat branch pipe 2 is cooled and gradually becomes a liquid, and when it joins the right header 1, it becomes completely liquid. The liquid refrigerant in the right header is discharged from the refrigerant outlet 5 provided at the lower end of the header. 4 in the figure
Is a side plate for protecting the corrugated fins. Although not shown in FIG. 5, some partition plates are provided in the header 1 so that the refrigerant may flow to the right, to the left, or meander. Many.

FIG. 1 is a perspective view of a parallel flow heat exchanger which is a first embodiment of the present invention. The parallel flow heat exchanger of this embodiment has one upper header pipe 1b horizontally arranged at the upper part and one lower header arranged parallel to the upper header pipe 1b below the upper header pipe 1b. The pipe 1a, a plurality of perforated flat branch pipes 2 vertically connecting the pipes 1a, corrugated fins 3 arranged so as to meander between the perforated flat branch pipes, and vertically outside the outermost corrugated fins 3 It is configured to include a side plate 4 arranged, a refrigerant inlet / outlet 6 connected to the upper header pipe 1b, and a refrigerant inlet / outlet 5 connected to the lower header pipe 1a. When using this parallel flow heat exchanger as an evaporator, when using the refrigerant inlet / outlet 5 connected to the lower header pipe 1a as the refrigerant inlet and the refrigerant inlet / outlet 6 of the upper header pipe 1b as the refrigerant outlet, and using it as the condenser, The refrigerant inlet / outlet 6 of the upper header pipe 1b is a refrigerant inlet, and the refrigerant inlet / outlet 5 of the lower header pipe 1a is a refrigerant outlet.

When the heat exchanger having the structure shown in FIG. 5 is used as an evaporator as it is, water droplets adhering to the corrugated fins 3 accumulate on the perforated flat branch pipes 2 arranged horizontally,
Since it is difficult to drain the water, the ventilation resistance increases and the heat exchange efficiency decreases. When the perforated flat branch pipe 2 is vertically arranged as shown in FIG. 1, the water droplets attached to the corrugated fins 3 quickly flow down vertically along the perforated flat branch pipe 2 arranged in the vertical direction. At this time, as the flow of the refrigerant, when used as an evaporator, it is better to flow from the bottom to the top. This is because the gas-liquid two-phase flow refrigerant evaporates to become vapor, and the density becomes smaller and rises. On the contrary, when used as a condenser, it is better to let the superheated vapor flow from top to bottom because the superheated vapor gradually becomes a liquid. The solid line arrow in FIG. 1 indicates the flow of the refrigerant in the case of the evaporator, and the broken line arrow indicates the flow of the refrigerant in the case of the condenser.

FIG. 2 shows a perspective view of a parallel flow heat exchanger according to a second embodiment of the present invention. The difference between the first embodiment and the second embodiment shown in FIG. 1 is how the refrigerant inlets and outlets 5 and 6 are attached, and since the other constituent elements are the same, the same parts are designated by the same reference numerals. The description is omitted. In this embodiment, as shown in FIG. 2, the refrigerant inlets / outlets 5 and 6 are mounted so as to be perpendicular to the refrigerant flow in the header and the refrigerant flow in the perforated flat branch pipe. With such a configuration, the kinetic energy of the refrigerant and the flow pattern of the refrigerant in the refrigerant inlet / outlet ports 5 and 6 do not directly affect the refrigerant distribution. Taking the refrigerant inlet as an example, the kinetic energy of the refrigerant collides with the wall of the header 1, recovers the pressure, and rises in static pressure. As a result, the pressure in the header 1 slightly changes depending on the location, but the flow pattern becomes almost uniform everywhere, so that the distribution of the refrigerant to the perforated flat branch pipe 2 is improved.

According to the present embodiment, the refrigerant inlet / outlet is installed so as to be perpendicular to the refrigerant flow in the header pipe and the refrigerant flow in the perforated flat branch pipe, so that the refrigerant is held in the refrigerant inlet / outlet. The distribution of the refrigerant can be improved without directly affecting the distribution of the refrigerant in the perforated flat branch pipe by the existing kinetic energy. That is, since the kinetic energy of the refrigerant in the refrigerant inlet collides with the wall of the header pipe and recovers the static pressure before flowing in the header pipe, it is considered that the refrigerant distribution is determined only by the static pressure distribution of the header. As a result, the refrigerant distribution is improved, and the performance of the parallel flow heat exchanger can be fully exerted.

FIG. 3 shows a third embodiment of the present invention. The embodiment shown in FIG. 3 is a further improvement of the second embodiment. The number of refrigerant inlets and outlets connected to the lower header pipe 1a and the upper header pipe 1b is plural, and the refrigerant header and outlet ports are connected to the lower header pipe 1a. It is different from the first embodiment in that the refrigerant inlet / outlet and the refrigerant inlet / outlet connected to the upper header pipe 1b are arranged at positions facing each other. Since the other constituent elements are the same as those in the second embodiment, the same constituent elements are designated by the same reference numerals and the description thereof will be omitted.
In this embodiment, the lower header pipe 1a and the upper header pipe 1b have the same number of refrigerant inlet / outlet ports 5a, 5b, respectively.
Refrigerant inlet / outlet 6a serving as a refrigerant outlet at the time of the evaporator is attached directly above refrigerant inlet / outlet 5a, and refrigerant inlet / outlet 6b is attached directly above refrigerant inlet / outlet pipe 5b. That is, the refrigerant inlet / outlet of the lower header pipe 1a and the refrigerant inlet / outlet of the upper header pipe 1b are characterized in that they are attached so as to be located at both ends of one perforated flat branch pipe.

The reason for such an arrangement will be described with reference to FIG. FIG. 4 schematically shows a static pressure distribution 8a in the lower header pipe (inlet header) 1a and a static pressure distribution 8b in the upper header pipe (outlet header) 1b when the heat exchanger is used as an evaporator. It is shown in. The static pressure in the inlet header 1a near the refrigerant inlet / outlet 5 is smaller than that in other portions because the refrigerant velocity is high. Similarly, since the refrigerant velocity near the refrigerant inlet / outlet 6 is high, the static pressure in the outlet header 1b in the vicinity thereof is lower than that in the other portions. The perforated flat branch pipe 2 connected to the portion where the static pressure is low in the inlet header 1a is connected to the portion where the static pressure is low in the outlet header 1b as well.
Are attached so as to be located at both ends of the same porous flat branch pipe 2. As a result, any porous flat branch pipe 2
The desired result is that the pressure difference between the inlet header 1a and the outlet header 1b becomes substantially equal, and the refrigerant distribution becomes uniform. In other words, by making the static pressure distribution 8a in the inlet header 1a and the static pressure distribution 8b in the outlet header 1b have the same shape, the refrigerant distribution is made uniform.

The above-described operation is the same in the case of a condenser in which the upper header pipe 1b serves as an inlet header and the lower header pipe 1a serves as an outlet header. In the case of a condenser, since the liquid produced by condensing the refrigerant gas has a higher density than the refrigerant gas, a large pressure is required to push this liquid upward. Therefore, as shown in FIG. 1, the condensate is the upper header 1b.
It is preferable to unidirectionally flow from the bottom to the lower header 1a.

Since the number of refrigerant inlet / outlet ports attached to the upper header and the number of refrigerant inlet / outlet ports attached to the lower header are the same, and the mounting positions are the same in the upper and lower headers, the static pressure distributions in the upper and lower headers have substantially the same shape. Next to
The refrigerant distribution is further improved, and the performance of the parallel flow heat exchanger can be maximized.

[0023]

As described above, according to the present invention, the following effects can be obtained.

When used as an evaporator, since the refrigerant inlet / outlet connected to the lower header pipe is used as a liquid refrigerant inlet and the refrigerant inlet / outlet connected to the upper header pipe is used as a refrigerant vapor outlet, the refrigerant liquid evaporates. The vapor becomes vapor, its density becomes smaller, and it flows vertically upward in the porous flat branch pipe, so that the flow of the refrigerant becomes stable. When used as a condenser, since the refrigerant inlet / outlet connected to the upper header pipe is used as the refrigerant vapor inlet and the refrigerant inlet / outlet connected to the lower header pipe is used as the liquid refrigerant inlet / outlet, the refrigerant vapor is gradually cooled,
As it becomes a liquid, it flows vertically downward in the perforated flat branch pipe, so the flow is also stable. As a result, a heat exchanger with a small refrigerant-side pressure loss can be provided as a parallel flow heat exchanger for a heat pump.

[Brief description of drawings]

FIG. 1 is a perspective view of a first embodiment of a parallel flow heat exchanger of the present invention.

FIG. 2 is a perspective view of a second embodiment of the parallel flow heat exchanger of the present invention.

FIG. 3 is a perspective view of a third embodiment of the parallel flow heat exchanger of the present invention.

FIG. 4 is a conceptual diagram showing an example of header static pressure distribution in a third embodiment of the present invention.

FIG. 5 is a perspective view when a conventional parallel flow heat exchanger is used as a condenser.

[Explanation of Codes] 1 ... Header pipe, 1a ... Lower header pipe, 1b ... Upper header pipe, 2 ... Perforated flat branch pipe, 3 ... Corrugated fins, 4 ... Side plate, 5 ... Refrigerant inlet / outlet (refrigerant inlet at evaporator) , 6 ... Refrigerant inlet / outlet (refrigerant outlet at the time of evaporator), 7 ...
Cooling air flow direction, 8a ... Static pressure distribution in evaporator inlet header, 8b ... Static pressure distribution in evaporator outlet header.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Yoshinaga 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Living Equipment Division, Hitachi, Ltd. (72) Hiroshi Kogure 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. (72) Inventor Ryoichi Hoshino, 6-224 Kaiyamacho, Sakai City, Osaka Prefecture, Showa Aluminum Co., Ltd. (72) Inventor, Nobuhiro Wakabayashi 6-224, Kaiyamacho, Sakai City, Osaka Showa Aluminum Co., Ltd. Within

Claims (4)

[Claims] 1. An upper header pipe horizontally arranged at an upper part, a lower header pipe horizontally arranged below the upper header pipe, and a plurality of perforated flat branch pipes connecting vertically between them. In the parallel flow heat exchanger consisting of, each of the upper header pipe and the lower header pipe is provided with a refrigerant inlet / outlet, and when the heat exchanger is used as an evaporator, the refrigerant inlet / outlet of the lower header pipe is a liquid refrigerant inlet, The refrigerant inlet / outlet of the upper header pipe operates as a refrigerant vapor outlet, and when the heat exchanger is used as a condenser, the refrigerant inlet / outlet of the upper header pipe serves as a refrigerant vapor inlet, and the refrigerant inlet / outlet of the lower header pipe serves as a liquid refrigerant outlet. A parallel flow heat exchanger for a heat pump, which operates. 2. The parallel flow heat exchanger for a heat pump according to claim 1, wherein the refrigerant inlet / outlet is vertically attached to the refrigerant flow in the header pipe and also vertically to the refrigerant flow in the perforated flat branch pipe. A parallel flow heat exchanger for heat pumps. 3. The parallel flow heat exchanger for a heat pump according to claim 2, wherein the number of refrigerant inlet / outlet ports connected to the upper header pipe and the number of refrigerant inlet / outlet ports connected to the lower header pipe are at least two, respectively. And, the number of the refrigerant inlet / outlet connected to the upper header pipe and the number of the refrigerant inlet / outlet connected to the lower header pipe are the same, and each refrigerant inlet / outlet has the same porous flat branch pipe connected to the upper header pipe and the lower header pipe. A parallel flow heat exchanger for a heat pump, which is arranged in pairs vertically near the position. 4. The heat pump parallel flow heat exchanger according to claim 3, wherein the refrigerant inlets and outlets are arranged at substantially equal intervals.