JP3952080B2 - Indoor unit - Google Patents

Description

The present invention relates to a heat exchanger and an indoor unit used as an evaporator or a condenser in a refrigeration cycle, and a method for manufacturing the heat exchanger, a heat exchanger using a non-azeotropic refrigerant mixture in the refrigeration cycle,
It is suitable for a multi-row cross flow fin tube type heat exchanger.

Conventionally, one of the forms of heat exchangers used as evaporators or condensers in refrigeration cycles is to exchange heat with air by configuring fins perpendicular to the tube axis outside the heat transfer tube, which is the refrigerant passage inside. There is a so-called crossflow fin tube type heat exchanger. This heat exchanger has an arrangement of heat transfer tubes arranged at equally spaced pitches, and is processed into a U shape by layering the fins with holes whose inner diameter is slightly larger than the outer diameter of the heat transfer tubes in advance. The outer surface of the heat transfer tube and the inner surface of the fin hole are brought into contact with each other by expanding the tube by applying pressure from the inside of the heat transfer tube.
Assemble and assemble.

In addition, from the viewpoint of the size of the equipment and heat transfer performance, the heat exchanger often requires two or more rows of heat transfer tubes on the air flow direction side. For example, as shown in Patent Document 1 What is known.

JP-A-63-17364

In the above-described conventional technology, the heat transfer tubes are arranged in two rows. However, the heat transfer tubes are configured as one row fin heat exchangers, and the heat exchangers are not stacked in two or more rows, so that it is not always easy to assemble.

The purpose of the present invention is to improve performance in consideration of the size of the heat exchanger, the optimization of the refrigerant passage, etc., when a refrigerant made by mixing two or more types of non-chlorinated fluorocarbons is used as an alternative refrigerant for R22 regulation. Is to plan.

Another object of the present invention is to provide a heat exchanger that improves the performance of the heat exchanger, increases the degree of freedom with respect to the required heat exchange capacity, and has good assemblability and is inexpensive.

In order to achieve the above object, the present invention comprises a heat exchanger used in an evaporator or a condenser of a refrigeration cycle, in which two rows of heat transfer tubes are arranged and formed in a square shape. In a four-direction blowout ceiling type indoor unit that sucks room air from the center by a centrifugal blower arranged at the approximate center of the shape and blows it in the radial direction, the working fluid of the refrigeration cycle is two or more types of non-chlorine fluorocarbons The liquid refrigerant side distributor to which one of the two rows of the heat transfer tubes is connected, the gas refrigerant side distributor to which the other is connected, and the outside of each of the two rows of heat transfer tubes In addition, the fins are arranged perpendicular to the axial direction of the heat transfer tube to form two rows of fins on the upstream side and fins on the downstream side with respect to the direction of air flow. Surround the area around the blower Each of the multi-stage paths that are arranged and distribute the refrigerant by the heat transfer tubes has a length equivalent to one reciprocal length of the heat exchanger and passes through the two rows of the fins. The heat transfer tube assembled to the fin on the upstream side in the air flow direction is connected to the liquid refrigerant side distributor, and the heat transfer tube assembled to the fin on the downstream side is connected to the gas refrigerant side distributor. The lengths of the two rows of fins connected are substantially the same, and the end faces of the two rows of heat transfer tubes are connected by a J-shaped connection tube.

Further, in the above, the heat transfer tube assembled to the fin on the upstream side in the air flow direction is connected to the liquid refrigerant side distributor, and the heat transfer tube assembled to the fin on the downstream side is connected to the gas refrigerant side. It is desirable to connect to a distributor.

Furthermore, in the above, so that both ends are the same after bending of the heat transfer tube,
It is desirable that the heat transfer tube on the outer peripheral side is lengthened in advance.

Further, in the above, it is desirable that a path is provided in which the same stage of the heat transfer tubes is connected so that the refrigerant passes through the two rows of the heat transfer tubes.

According to the present invention, a refrigerant formed by mixing two or more types of non-chlorinated fluorocarbons is used as an alternative refrigerant, and the refrigerant passage is optimized to improve performance and increase the degree of freedom with respect to the required heat exchange capacity. As a result, the assemblability is good and the cost can be reduced.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing a structure of a heat exchanger of an indoor unit in an air conditioner using a vapor compression refrigeration cycle, FIG. 2 is a side view showing a path arrangement of an embodiment, and FIG. 3 is an embodiment. FIG. 4 is a top view showing another embodiment, FIG. 5 is a top view showing another embodiment, and FIG. 6 shows a production method in one embodiment. FIG. 7 is a perspective view, FIG. 7 shows a production method according to an embodiment, a side view showing fin bending, and FIG. 8 is a side view showing a conventional pass arrangement.

This indoor unit is generally of a type called a four-direction blowout ceiling embedded type, and is installed so as to suck indoor air from the center, blow out the air in a radial direction by a centrifugal blower, and surround the periphery of the centrifugal blower After exchanging heat with the heat exchanger, it is sent to the room.
The arrows in the figure indicate the direction of air flow.

The figure shows a heat exchanger in which two fins with the same number of stages (four stages) are stacked to form two rows, and heat is exchanged with air by providing fins that are perpendicular to the axial direction of the heat transfer tubes that serve as refrigerant passages. This is a so-called cross flow fin tube type configuration.

In the four-direction blowout ceiling embedded type, it is necessary to install a centrifugal blower at the center and install a heat exchanger so as to surround it, and since it is installed behind the ceiling, the height direction should be as low as possible Is desirable. Therefore, the heat exchanger is relatively long.
Therefore, the length of the path for distributing the refrigerant is preferably the shortest path so as to minimize the pressure loss, and for each U-shaped heat transfer tube corresponding to one reciprocation in the length direction, One pass is preferred.

Thus, when it is necessary to lengthen the length of a fin, the length of a heat exchanger tube also becomes long. In order to reduce the pressure loss due to the refrigerant flow, it is necessary to form one path with one heat transfer tube in which the length of each path for distributing the refrigerant passage is processed into a U shape.

In the present embodiment, as shown in FIG. 2, connecting pipes 5 are connected to fins 1 in the rear row and fins 2 in the front row with respect to the air flow. As a result, the refrigerant passes through the fin 1 and the fin 2 in each path by the heat transfer tube for distributing the refrigerant, so that the difference in the amount of heat exchange between the paths is reduced, and the distribution of the refrigerant flow rate to each path is also compared. Can be set easily. The distribution of the refrigerant flow rate can be adjusted by adjusting the resistance of the mesh tube, for example.

On the other hand, in the conventional path arrangement as shown in FIG. 8, since two fins are stacked, one path is divided between the fin 1 and the fin 2. Therefore, it is difficult to distribute the refrigerant flow rate in each pass with the fin 2 that is on the upstream side of the air flow and has a large heat exchange amount and the fin 1 that is on the downstream side and the difference between the air temperature and the refrigerant temperature becomes small. Become.

In the present embodiment, the gas refrigerant distributor 3 is connected to the fin 1 in the rear row on the air wake side,
When the liquid refrigerant distributor 4 is connected to the fins 2 in the front row and used for heating, the liquid refrigerant distributor 4 is arranged in a counterflow manner with respect to the air flow direction. Thereby, since the difference of air temperature and refrigerant | coolant temperature can be enlarged also in the fin 1, the improvement of condensation performance can be aimed at.

Furthermore, since the gas refrigerant distributor 3 and the liquid refrigerant distributor 4 are completely separated, the height of the connection portion due to the manufacturing error of the fins may be shifted, and manufacturing problems are reduced.

In addition, since the two stages form a set as in the conventional example shown in FIG. 8, only an even number of stages can be selected. However, in this embodiment, since one stage can be selected, the required heat exchange capacity On the other hand, the degree of freedom of design can be expanded.

Furthermore, since it is sufficient to change the height of the heat exchanger and the height of the gas refrigerant distributor at equal pitches with respect to the difference in the number of stages, it is very advantageous for standardized design.

In the embodiment shown in FIG. 3, the fins are disposed in the air passage portion without any difficulty.
The lengths of the fins 1 in the rear row and the fins 2 in the front row are made longer by the difference in the circumferential length of the bent portion.

On the other hand, the embodiment shown in FIGS. 4 and 5 uses the same fins with the fins 1 and 2 having the same length. In the example of FIG. 4, the fin 1 is shortened by an amount corresponding to the difference in circumferential length, with the end surface on the connection pipe 5 side being bent. Further, in FIG. 5, the heat exchanger having the same length is bent with respect to the gas refrigerant distributor 3 and the liquid refrigerant distributor 4, so that the end surface on the side of the connecting pipe 5 does not appear, but the shape of the connecting pipe 5 is J-shaped. To compensate for the difference in length.

4 and 5 can have only one type of the length of the fins 1 and 2, the time required for changing the setup of the manufacturing apparatus for the length change can be shortened, and the productivity is improved. It is also advantageous for standardization.

FIG. 6 shows a manufacturing method procedure of the heat exchanger according to the present invention, in which a heat transfer tube is inserted into each row of two fins and expanded, bent into a desired shape, and a heat transfer tube between the rows. Are connected by a connecting pipe. Then, the U-shaped part is cut.

Next, the inner diameter of the cut end portion is expanded, and a bend pipe as a connection pipe is obliquely transferred to and connected to the front and rear rows.

As a result, the manufacturing process of the heat exchanger can be made the same as before until the pipe expansion, and the height of the connection portion may be slightly shifted due to a manufacturing error, and the production becomes easy. Furthermore, since the U portion cut off by cutting can be used, it is economical.

The above embodiment can be applied to a refrigerant that is a non-azeotropic refrigerant mixture obtained by mixing two or more kinds of non-chlorinated fluorocarbons as the working fluid of the refrigeration cycle. According to this, the size is reduced, the price is low, and the performance is not impaired even though the refrigerant is a non-azeotropic refrigerant mixture.

It is a perspective view which shows the structure of the heat exchanger of the indoor unit in an air conditioner. It is a side view which shows the path | pass arrangement | sequence of one Embodiment. It is a top view which shows one embodiment of FIG. It is a top view which shows other embodiment. It is a top view which shows other embodiment. It is the perspective view of the part of a connecting pipe which shows the production method in one embodiment. It is a side view which shows the production method in one embodiment, and shows the bending process of a fin. It is a side view which shows the conventional path | pass arrangement | sequence.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Fin, 3 ... Gas refrigerant distributor, 4 ... Liquid refrigerant distributor, 5 ... Connection pipe, 6 ... Centrifugal blower.

Claims (2)

Centrifugal blower that is used in an evaporator or condenser of a refrigeration cycle, has a heat exchanger formed in a mouth shape by arranging two rows of heat transfer tubes, and is arranged at substantially the center of the mouth shape In the four-direction blowout embedded indoor unit that sucks room air from the center and blows it in the radial direction,
The working fluid of the refrigeration cycle is a refrigerant formed by mixing two or more types of non-chlorinated fluorocarbons,
A liquid refrigerant side distributor to which one of the two heat transfer tubes is connected; a gas refrigerant side distributor to which the other is connected;
The fins are arranged outside the heat transfer tubes in the two rows perpendicularly to the axial direction of the heat transfer tubes, and are configured in two rows of fins on the upstream side and fins on the downstream side with respect to the air flow direction. places the fins of the two rows so as to surround the periphery of the centrifugal fan,
Each multi path for distributing the refrigerant by the heat transfer tubes, their length as well as in a substantially length of one round trip length of the heat exchanger, and configured to pass through the fins of the two rows ,
Connect the heat transfer tube assembled to the fin on the upstream side with respect to the direction of air flow to the liquid refrigerant side distributor, connect the heat transfer tube assembled to the fin on the downstream side to the gas refrigerant side distributor,
The length of the two rows fins are substantially the same, the indoor unit characterized in that the end face of the heat transfer tube of the two rows are connected by J-shaped connecting pipe.
Oite to claim 1, an indoor unit, wherein the second column the heat transfer tubes of the same stage of the heat transfer tube so as to pass the refrigerant is provided with a connection path.

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