JPH0933189A - Heat exchanger for outdoor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict an adhesion speed of frost to a heat exchanger, and delay deterioration of heat exchanger efficiency by disposing the heat exchanger on the upstream side of an air flow with respect to a heat exchanger body, and providing a refrigerant tube so as for it to traverse in a plurality of times a plane located parallely to the heat exchanger body. SOLUTION: A refrigerant flowing into a refrigerant tube 2 heat-exchanger with air just before it flows into a heat exchanger body, and joins with the air at an outlet tube. Air A directed to the refrigerant tube 2 is dehumidified because water contained in the air adheres to the refrigerant tube 2 as frost C upon heat exchanging with the refrigerant flowing through the refrigerant tube 2. Since the dehumidified dry air B is directed to the heat exchanger body, even when the heat exchanger body is of a multi-flow type having a higher heat exchange efficiency, adhesion of frost can be delayed upon heat exchanging with the refrigerant flowing into the heat exchanger body, and further a time interval of defrosting operation can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outdoor unit heat exchanger used in, for example, a heat pump type air conditioner.

[0002]

2. Description of the Related Art Recently, as an air conditioner, a heat pump type air conditioner having both cooling and heating functions has become mainstream. When such a heat pump type air conditioner is used for heating operation in winter, the heat exchanger in the outdoor unit operates as an evaporator, so that the temperature of the heat exchanger becomes lower than the outside air temperature. Therefore, moisture in the air becomes frost and adheres to the heat exchanger, and as the adhered frost increases, the flow of air ventilated through the heat exchanger is obstructed, and the heat exchange efficiency of the heat exchanger gradually increases. Gradually decreases. Therefore, if the amount of frost on the heat exchanger exceeds a certain value, it is necessary to perform defrosting operation to recover the heat exchange efficiency, but during this time, the heat exchanger does not operate as an evaporator, You will be forced to stop. Therefore, it is desired to lengthen the time until the amount of frost adhering to the heat exchanger reaches a certain value or more to lengthen the defrosting operation interval.

Therefore, as a heat exchanger for delaying a decrease in heat exchange efficiency due to frost formation, Japanese Patent Publication No. 6-12230 discloses that a tubular or column-shaped dummy is placed on the windward side with respect to the air flow passing through the heat exchanger. By placing a part of the fins of the heat exchanger in the dead water region formed by the dummy, the frost rate of the fins in the dead water region is reduced, and the frost formation in the depth direction of the fins is accelerated by the accelerated air flow. And a heat exchanger that delays clogging due to frost is disclosed. However, even with this heat exchanger, although the defrosting operation interval was slightly longer, it did not reach a satisfactory level.

On the other hand, from the viewpoint of installation space and the like, there is a demand for making the outdoor unit of an air conditioner small, and in order to meet this demand, a multi-flow type heat exchanger having a high heat exchange rate has recently been receiving attention. Such a multi-flow heat exchanger has a large number of tubes arranged in parallel, both ends of each tube are connected in communication with a pair of hollow headers, and fins are arranged between adjacent tubes. Are doing When such a multi-flow type heat exchanger is used in winter, it has higher heat exchange efficiency, so it is more likely to frost than conventional heat exchangers, and because the fins are close together, frost quickly causes clogging. Occurs, and the flow of air is obstructed, and the heat exchange efficiency deteriorates early. Therefore, the multi-flow type heat exchanger can reduce the size of the outdoor unit due to its high heat exchange efficiency, but it must be defrosted more frequently than the conventional heat exchanger,
This has been one of the problems in applying the multi-flow heat exchanger to the outdoor unit of the air conditioner.

The present invention has been made in order to solve the above problems, and provides a heat exchanger for an outdoor unit, which suppresses the rate of frost adhering to the heat exchanger and delays the decrease in heat exchange efficiency. The purpose is.

[0006]

The heat exchanger for an outdoor unit according to the present invention has a heat exchanger main body for exchanging heat with the circulating air, and the circulating air to the heat exchanger main body. The gist of the present invention is that the refrigerant pipe is arranged on the windward side and is provided in such a manner that it crosses a plane parallel to the heat exchanger body a plurality of times.

With the above-mentioned structure, the air ventilated through the outdoor unit heat exchanger first exchanges heat with the refrigerant flowing in the refrigerant pipe on the windward side, and then in the heat exchanger body. It will exchange heat with the flowing refrigerant. Here, when the outdoor unit heat exchanger is operating as an evaporator, since the refrigerant having a temperature lower than the outside air flows in the heat exchanger main body and the refrigerant pipe, the moisture in the air first flows into the refrigerant pipe. As a result, the dehumidified dry air flows to the heat exchanger body located on the downstream side of the air that is attached as frost, and frost formation on the heat exchanger body is suppressed. Therefore, since the growth of frost adhering to the heat exchanger body is delayed, the defrosting operation interval can be extended, and stable and high heat exchange efficiency can be maintained for a long time.

Further, the heat exchanger main body includes a large number of tubes arranged in parallel, a pair of hollow headers having both ends of the tubes communicatingly connected to each other, and fins arranged between the adjacent tubes. In the case of a multi-flow type equipped with and, it is possible to provide a small heat exchanger that can be continuously operated while maintaining a higher heat exchange efficiency for a long period of time.

Further, when the refrigerant pipe is connected in parallel with the heat exchanger body with respect to the passage of the refrigerant flowing inside, the pressure loss of the refrigerant due to the refrigerant pipe does not directly affect the heat exchanger body. It is possible to freely set the diameter, length and handling of the refrigerant pipe. Therefore, it is possible to set the optimum shape of the refrigerant pipe, which has a high dehumidifying effect and is less likely to obstruct the airflow to be ventilated.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to an aluminum outdoor heat exchanger used for a heat pump type air conditioner.

FIG. 1 is a diagram showing an embodiment of the present invention, in which (1) is a heat exchanger main body, and (2) is a heat exchange with respect to a flow of air (shown by an arrow W in FIG. 1). It is a meandering refrigerant pipe arranged on the upstream side of the container body (1).

The heat exchanger body (1) has a large number of flat tubes (3) arranged in parallel, and
A pair of hollow headers (4) on each end of each tube (3)
It is composed of a multi-flow type heat exchanger in which the corrugated fins (5) are connected in communication with (4) and the corrugated fins (5) are arranged between the adjacent tubes (3), and the lengths of the tubes (3) and the fins (5). By bending a part of the direction at right angles to the width direction, the whole is formed in an L shape in plan view.

The tube (3) is a so-called harmonica tube which is made of an extruded aluminum material and whose interior is divided into a plurality of chambers by partition walls to improve heat transfer performance and pressure resistance. An electric resistance welded tube may be used. Also, the corrugated fin (5)
Is a corrugated sheet material having substantially the same width as the tube (3) and cut and raised louvers. An aluminum brazing sheet in which a brazing material layer is clad is used as the sheet material. When an electric braided tube of an aluminum brazing sheet is used for the tube (3), an aluminum bare material having no brazing material layer may be used as the fin.

The header (4) is formed by forming an aluminum brazing sheet into a pipe having a circular cross section, and a tube insertion hole is indirectly formed in the longitudinal direction on the peripheral surface, and the tube insertion hole is formed in the tube insertion hole. Both ends of each tube (3) are insert-connected and brazed. The upper and lower end openings of each header (4) are closed by the lid (10).

A refrigerant inlet pipe (6) is connected to the lower peripheral surface of one header (4), and the other header (4) is connected.
A refrigerant outlet pipe (7) is connected to the upper peripheral surface of the.

The heat exchanger body (1) applicable to the present invention is not limited to the multi-flow type adopted in the embodiment, but is applicable to all heat exchangers that exchange heat with circulating air. obtain.

The refrigerant pipe (2) is composed of one thin pipe,
One end thereof is connected to the refrigerant inlet pipe (6), and the other end is connected to the refrigerant outlet pipe (7). As a result, the heat exchanger body (1) and the refrigerant pipe (2) are connected in parallel with respect to the passage of the refrigerant flowing inside, and the refrigerant supplied to the refrigerant inlet pipe (6) is the heat exchanger body. The flow is divided into (1) and the refrigerant pipe (2). Further, the longitudinal middle portion of the refrigerant pipe (2) is vertically arranged at a position close to the heat exchanger body (1) in such a manner that the refrigerant pipe (2) horizontally crosses a plane parallel to the heat exchanger body (1). Multiple straight pipe parts (2
1) and the curved pipe portion (22) that connects the ends of the adjacent straight pipe portions (21) to each other form a meandering circuit. The refrigerant pipe (2) is also bent into an L shape in plan view along the heat exchanger body (1), and both ends thereof are fixed to the upper and lower lids (10) of the headers (4) to form a pair of U-shapes. By fixing the end of the straight pipe part (21) to the holding plate (8), the straight pipe part (21) is held parallel to the windward side of the heat exchanger body (1).

The refrigerant pipe (2) contacts the circulating air to dehumidify it before passing through the heat exchanger body (1), and sends dry air to the heat exchanger body (1). Therefore, it is provided to reduce the frost formation rate in the heat exchanger body (1). However, if the space between the adjacent straight pipe parts (21) of the refrigerant pipe (2) located on the front surface of the heat exchanger body (1) is narrow, the air flow is obstructed and the amount of air is insufficient, resulting in heat exchange efficiency. Cause a decrease in On the other hand, if the space between the straight pipe portions (21) is too wide, the amount of dehumidification by the refrigerant pipe (2) decreases, and the frost formation rate in the heat exchanger body (1) cannot be expected to decrease. Therefore, the straight pipe part (21)
The interval between them may be determined in consideration of the degree of obstruction of the air flow and the amount of dehumidification, in other words, the heat exchange efficiency of the heat exchanger body (1) and the frost formation rate. Further, it is preferable to dispose the straight pipe portion (21) in front of the tube (3) along the tube (3) since the flow of the air passing through the fins is not so hindered. The straight pipe (2
1) The intervals between them do not have to be set to be the same.

As the refrigerant pipe (2), one pipe may be made to meander as in this embodiment, but a plurality of straight pipes are arranged in parallel and both ends thereof are formed into a pair of hollow headers. Those connected in communication may be used. Further, it may be connected in series with the heat exchanger body (1).

When the heat exchanger according to the illustrated embodiment is used as an outdoor unit for a room air conditioner, it operates as an evaporator in winter, and a liquid refrigerant or a partially gasified refrigerant flows from the inlet pipe (6) to the header (6). After flowing into 4), it divides into each tube (3). The refrigerant flowing into the tube (3) exchanges heat with the air ventilated in the air circulation gap including the corrugated fins (5) while flowing through the tube (3), and is gasified to reach the header (4). After that, it flows out of the device through the upper outlet pipe (7). On the other hand, the refrigerant flows into the refrigerant pipe (2) branched from the inlet pipe (6) as in the heat exchanger body (1). The refrigerant flowing into the refrigerant pipe (2) exchanges heat with the air immediately before flowing into the heat exchanger body (1), and joins at the outlet pipe (7) of the heat exchanger body (1).

Thus, as shown in FIG. 2, the air (A) ventilated through the refrigerant pipe (2) contains moisture contained in the air during heat exchange with the refrigerant flowing through the refrigerant pipe (2). Adheres to the refrigerant pipe (2) as frost (C) and is dehumidified. Since the dry air (B) dehumidified by the refrigerant pipe (2) is ventilated through the heat exchanger body (1), even if the heat exchanger body (1) is a multi-flow type having high heat exchange efficiency. ,
It is possible to delay the adhesion of frost when exchanging heat with the refrigerant that has flowed into the heat exchanger body (1), and thus to extend the defrosting operation interval.

Next, FIG. 3 shows another embodiment according to the present invention. In this embodiment, fins (9) are attached to the refrigerant pipe (2). Note that, in FIG. 3, parts having the same names as those in the embodiment shown in FIGS.

The fins (9) are arranged so that they are parallel to the air flow ventilated through the heat exchanger body (1).
It is a plate-shaped fin provided in. Thus, by providing the fins (9) on the refrigerant pipe (2), the refrigerant pipe (2)
The heat exchange between the refrigerant and the air flowing therethrough can be promoted, and the dehumidifying effect can be improved. In this case, by making the fins (9) parallel to the air flow, the dehumidification effect can be improved without obstructing the air flow ventilated by the heat exchanger body (1) as much as possible.

There are no particular restrictions on the shape and size of the fins (9), their intervals, and the angle with respect to the air flow. It may be appropriately set in consideration of the degree of air inhibition and the dehumidification amount. As a method of attaching the fin (9) to the refrigerant pipe (2), a hole slightly larger than the outer diameter of the refrigerant pipe (2) is provided in the fin (9), and the refrigerant pipe (2) is inserted through the hole. A so-called expansion type in which the rear refrigerant pipe (2) is expanded to fix the fins, or a C-shaped hole that is slightly smaller than the outer diameter of the refrigerant pipe (2) is provided at the end of the fin (9), 2) may be a so-called click-type type in which the opening portion of the hole is pressed and forcibly fitted, and fixed in a held state.

[0025]

The present invention has been made as described above, and the heat exchanger for the outdoor unit is composed of the heat exchanger main body and the refrigerant pipe located upstream of the air flow passing through the heat exchanger main body. Since the refrigerant flows through the refrigerant pipe in the same manner as the heat exchanger body, the air ventilated through the outdoor unit heat exchanger first undergoes heat exchange with the refrigerant in the refrigerant pipe. Moisture in the air adheres to the refrigerant pipe as frost and is dehumidified. Next, this dehumidified air is passed through the heat exchanger body to exchange heat,
Frost formation in the heat exchanger body is suppressed, and the time until the heat exchange efficiency is reduced due to the air flow being obstructed due to frost formation becomes longer. As a result, the defrosting operation interval can be set longer than that of the conventional air conditioner. Also,
If this invention is applied to a multi-flow type heat exchanger having high heat exchange efficiency, the outdoor unit can be downsized and it is not necessary to shorten the defrosting operation interval. Can be fully exerted.

In addition, Japanese Patent Publication No. 6-12 described in the prior art.
No. 230, the rod-shaped dummy arranged on the windward side of the heat exchanger body has no dehumidifying effect, and the air flow is simply disturbed by the dummy to form the dead water region and the acceleration region, and the fins are attached in the depth direction. It only makes the amount of frost uniform and secures an air passage. On the other hand, in the present invention, since the refrigerant is circulated in the refrigerant pipe arranged on the windward side to dehumidify the circulating air by heat exchange, the amount of frost formed on the heat exchanger main body located downstream can be reduced. Therefore, a sufficient amount of dehumidification can be secured even if the refrigerant pipe is configured with a small-diameter pipe, so that the inconvenience of obstructing the air flow in the refrigerant pipe can be suppressed as much as possible, and high heat exchange efficiency can be maintained for a long period of time. It can be done as a bowl.

Further, when the refrigerant passages of the heat exchanger main body and the refrigerant pipe are parallel, it is possible to prevent the pressure loss of the refrigerant due to the refrigerant pipe from directly affecting the heat exchanger main body. Therefore, since the diameter, length, and handling of the refrigerant pipe can be freely set, it is possible to set the optimum shape of the refrigerant pipe that has a high dehumidifying effect and that does not easily obstruct the air flow.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an outdoor unit heat exchanger according to the present invention.

FIG. 2 is a sectional view showing a part of the above embodiment.

FIG. 3 is a perspective view showing another embodiment according to the present invention.

[Explanation of symbols]

 1 ... Heat exchanger main body 2 ... Refrigerant tube 3 ... Tube 4 ... Header 9 ... Fin

Claims (3)

[Claims] 1. A heat exchanger main body for exchanging heat with circulating air, and a heat exchanger main body, which is arranged on the windward side of the circulating air with respect to the heat exchanger main body, and which is disposed a plurality of times in a plane parallel to the heat exchanger main body. A heat exchanger for an outdoor unit, comprising a refrigerant pipe provided in a traversing manner. 2. A heat exchanger body comprising a large number of tubes arranged in parallel, a pair of hollow headers in which both ends of these tubes are connected for communication, and fins arranged between the adjacent tubes. The heat exchanger for an outdoor unit according to claim 1, wherein the heat exchanger is a multi-flow type. 3. The heat exchanger for an outdoor unit according to claim 1, wherein the refrigerant pipe is connected in parallel with the heat exchanger main body with respect to the path of the refrigerant flowing inside.