JPH085197A - Refrigerant condenser - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost and to design with high heat exchanging rate by improving the assembling properties. CONSTITUTION:A zigzag tube 14 is connected to a pair of headers 12, 13 to be refrigerant inlet and outlet to form a refrigerant condenser 11. The tube 14 is so folded in a zigzag state by the number N of the times of foldings at the flat tube 15 having an inner tube diameter de of 0.60<=de<=1.15. Corrugated fins 16 are attached to the lateral entirety between the tube 15. The number N (integer) of the times of foldings of the tube 14 and the effective heat exchanging width W (m) are so set as the following formula for the diameter de (mm) of the tube 15. (N+1)W=0.4+1.18de to 0.7+1.18de.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant condenser suitable for use in a refrigerating cycle such as a car air conditioner or a room air conditioner.

[0002]

2. Description of the Related Art In recent years, as a refrigerant condenser (condenser) used in, for example, a car air conditioner, Japanese Patent Publication No. 5-8775.
The one shown in No. 2 has been developed. As shown in FIG. 5, the refrigerant condenser 1 is provided so as to span a large number of flat tubes 3 which are long in the left-right direction between the cylindrical pipe-shaped headers 2 and 2 located on the left and right, and the flat tubes A corrugated fin 4 is provided between the three. Further, although not shown, a separator that partitions the inside of the header 2 in the vertical direction is provided at an appropriate position in the header 2 so that the refrigerant flows in a meandering manner while changing the flow direction in the header 2. It is like this.

By the way, when manufacturing such a refrigerant condenser 1, a flat tube 3 is formed on a side surface of the header 2.
While a plurality of notches 2a to which the ends of are joined are formed at a predetermined interval, flat tubes 3 and corrugated fins 4 having a predetermined length are alternately laminated by, for example, brazing to form a core 5. Then, the core 5 is joined so that the end of each flat tube 3 fits into each notch 2a of the header 2, whereby the refrigerant condenser 1 can be obtained.

[0004]

However, in the conventional refrigerant condenser 1 described above, a large number of flat tubes 3 have to be joined to the header 2, respectively, and the number of joints is extremely large. There is a drawback that the assembly work becomes complicated and the manufacturing cost becomes high. Moreover, in order to join the flat tubes 3 to the cuts 2a formed in the header 2, high dimensional accuracy is required for stacking the flat tubes 3 and the corrugated fins 4 when forming the core 5.
From this point as well, there was a problem that assembly workability was poor.

Further, in the conventional refrigerant condenser 1, it has been known that increasing the number of turns of the refrigerant passage or decreasing the passage cross-sectional area contributes to the improvement of the heat exchange rate. The optimum number of turns of the refrigerant passage for the refrigerant condenser has not been specified yet. Therefore, it is desired to clarify the condensation distance that can improve the heat exchange rate.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a refrigerant condenser which is excellent in assembling ability, can reduce the manufacturing cost, and can be designed to have a high heat exchange rate. To provide.

[0007]

The refrigerant condenser of the present invention comprises:
A pair of headers that form an inlet and an outlet of the refrigerant, and one or more meandering tube bodies that are formed by folding a flat tube into a meandering shape having an effective heat exchange width W and that both ends thereof are connected to the pair of headers, respectively. The number of turns N (integer) of each of the meandering tube bodies and the effective heat exchange width W (unit m) are equivalent to the pipe equivalent diameter de (unit mm: where de) ≦ 1.15), (N + 1) W = 0.4 + 1.18de to 0.7 + 1.1
It is characterized by being set as 8 de (the invention of claim 1). Further, in this case, it is more effective if the in-tube equivalent diameter de (unit: mm) of the flat tube is set to 0.60 ≦ de ≦ 1.15 (the invention of claim 2).

[0008]

According to the refrigerant condenser of claim 1 of the present invention, the pair of headers are connected to both ends of a meandering tube body which is formed by folding the flat tube in a meandering manner at a predetermined number of folding times N. Therefore, the number of flat tubes, that is, the number of meandering tube bodies per se, is greater than that in the case where a predetermined number of turns is obtained with a separator from a state where a large number of linear tubes are hung between a pair of headers. The number of joints can be greatly reduced by reducing the number of joints. Note that the number of meandering tube bodies is appropriately set based on the required flow rate of the refrigerant, and may be connected in parallel between a pair of headers.

By the way, in the refrigerant condenser, it is possible to increase the flow rate of the refrigerant and increase the heat transfer coefficient by lengthening the refrigerant passage and increasing the condensation distance.
There is a circumstance in which the pressure loss in the pipe increases and the refrigerant pressure decreases, which causes the condensing temperature to decrease. On the contrary, when the condensation distance is reduced, the pressure loss is reduced, but the heat transfer coefficient inside the tube is reduced and the performance is reduced. Therefore, the performance of the refrigerant condenser is determined by the balance between the improvement of the heat transfer coefficient and the pressure loss, and the two influence each other.

Therefore, the inventors of the present invention have proposed a refrigerant condenser using a flat tube having a small pipe area to optimize the heat exchange rate by optimizing the balance between the improvement of the heat transfer rate and the pressure loss. Experiments and researches have been repeated to clarify the condensation distance so that, for the flat tube equivalent diameter de (specifically de = 4 × [cross-sectional area] / [wet edge length]) The optimum range of the condensation distance L has been found.

That is, in the case of a small flat tube having a pipe passage area having a pipe equivalent diameter de of less than 1.15 mm, which corresponds to the diameter when the cross section is converted into a circular cross section, the pipe equivalent diameter de (unit mm ), The heat exchange rate becomes optimum when the condensation distance L (unit m) is set to L = 0.4 + 1.18de to 0.7 + 1.18de. In the meandering tube body, this condensation distance L can be expressed as L = (N + 1) W using the effective heat exchange width W and the number of times of folding back N. Therefore, (N + 1) W = 0.4 + 1.18de to 0.7 + 1.1
By setting it as 8 de, the heat exchange rate as the refrigerant condenser can be optimized.

At this time, as the flat tube,
It is extremely effective to use a pipe having an equivalent diameter de in the pipe of 1.15 mm or less. However, even if the equivalent pipe diameter de of the flat tube is too small, it is difficult to manufacture the flat tube. In practice, it is preferable to use a pipe having an equivalent diameter de of 0.06 mm or more (invention of claim 2).

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a refrigerant condenser for a car air conditioner will be described below with reference to FIGS. First, although not shown, in a refrigeration cycle of a car air conditioner, as is well known, a compressor (compressor) that compresses a gas refrigerant, and a high-temperature, high-pressure refrigerant discharged from this compressor is condensed into a liquid refrigerant. Refrigerant condenser 11 (condenser), receiver for performing gas-liquid separation of refrigerant and temporary storage of liquid refrigerant, expansion valve for rapidly expanding liquid refrigerant from this receiver into a low-temperature, low-pressure mist state, An evaporator (evaporator) that heats and vaporizes the atomized refrigerant from the expansion valve with the outside air is connected to the closed loop in order by the refrigerant pipe line while the required amount of refrigerant is sealed inside. ing.

FIG. 1 schematically shows the overall configuration of the refrigerant condenser 11 according to this embodiment. Here, the refrigerant condenser 11 includes a pair of headers 12 and 13 located on the left and right in the figure.
In addition, for example, two meandering tube bodies 14, 14 are joined together. Of these, the headers 12 and 13 both have a cylindrical shape (the axial direction is perpendicular to the paper surface), and for example, one header 12 constitutes an inlet into which a high-temperature, high-pressure gas refrigerant from the compressor is introduced, and the other one. The header 13 constitutes an outlet for letting out the liquid refrigerant toward the receiver. Although not shown, these headers 1
On the outer peripheral surface portions of the reference numerals 2 and 13, there are formed notches which are long in the axial direction and which are fitted and connected to the end portions of the meandering tube body 14.

The meandering tube body 14 is formed by folding flat tubes 15 which are flat in the horizontal direction in the vertical direction and are folded back to the left and right in a meandering shape. In this embodiment, the number of turns N is 4,
The flat tubes 15 are in a state of being laminated in five stages, so to speak. Furthermore, so-called laminated flat tubes 1
A radiating fin, for example, a corrugated fin 16 for promoting heat exchange is additionally provided between the five members by brazing, for example, over the entire lateral direction. The portion provided with the corrugated fins 16 effectively acts on heat exchange, and the width dimension in the left-right direction is the effective heat exchange width W.

In this case, in this embodiment, as the flat tube 15, as shown in FIG. 2 (a), a tube having a partition 15a extending in the flow direction of the refrigerant to divide the flow path is adopted. . Such a flat tube 15 is relatively easily obtained by extrusion molding.
At this time, the flat tube 15 has, for example, a height (thickness) dimension of 1.7 mm and a width dimension of 16 mm. In addition, the flat tube 15 has a height dimension of 3 to
It is desirable to use one having a width of 1 mm and a width of 8 to 20 mm, and the corrugated fin 16 has a height of 10 mm.
It is desirable to set it to ~ 6 mm.

Thus, the equivalent pipe diameter de (unit: mm) corresponding to the diameter of the flat tube 15 when the cross section (pipe area) is converted into a circular cross section is set to 0.60≤de≤1.15. Has been done. The pipe line area de is specifically de
= 4 × [cross-sectional area] / [wet edge length].

As a flat tube 17 of a different type, a corrugated spacer 17b is inserted into a tube 17a which is formed in a state where no partition is present inside, as shown in FIG. 2 (b). Similar to the flat tube 15, it is also possible to use a tube which is formed inside to form a partition that extends in the flow direction of the refrigerant and divides the flow path.

Now, in this case configured as described above, 2
The individual meandering tube bodies 14 and 14 are connected to the headers 12 and 13, respectively, in the state where they are vertically stacked. At this time, both end portions of each meandering tube body 14 are bent in the vertical direction so that they can be connected to the headers 12 and 13, and the ends thereof are notches formed in the outer peripheral surface portions of the headers 12 and 13. It is adapted to be fitted and joined to the portion from the outer peripheral direction. This constitutes the refrigerant condenser 11. A corrugated fin 16 is also provided in a portion between the lower meandering tube body 14 and the upper meandering tube body 14. Further, end plates 18 are provided at both upper and lower ends.

In the thus constructed refrigerant condenser 11, the number N of folding back of each meandering tube body 14 (integer) and the effective heat exchange width W (unit m) are equivalent to the inside of the flat tube 15. For diameter de (unit mm),
It is set so as to satisfy the following expression (1). (N + 1) W = 0.4 + 1.18de to 0.7 + 1.18de (1)

As a specific example, for example, the number of turns N =
4 and the equivalent pipe diameter de = 0.9 mm, the effective heat exchange width W is set to about W = 290 to 350 mm. Of course, the value of the equivalent diameter de in the flat tube 15 is 0.
It can be appropriately set within the range of 60 ≦ de ≦ 1.15, and accordingly, the number of folding back N and the effective heat exchange width W can take various values within the range of the above formula (1).

Since a refrigerant condenser for a car air conditioner is generally used with a core width of about 300 to 800 mm, the effective heat exchange width W is equivalent to W = 300 to 800 mm.
It is set to a degree and the number of turns N is changed accordingly.
Also, N is set to about 1 to 7 times. Further, the number of the meandering tube bodies 14 of the refrigerant condenser 11 is appropriately set based on the required flow rate of the refrigerant.

In the refrigerant condenser 11 configured as described above, the pair of headers 12 and 13 has a meandering tube formed by folding the flat tube 15 in a meandering manner at a predetermined number of folding times N. Since both ends of the body 14 are connected, a predetermined number of turns is obtained by the separator from a state in which a large number of linear flat tubes 3 are hung between a pair of headers 2 and 2 as in the conventional case. Compared with the refrigerant condenser 1, the number of the flat tubes 15, that is, the number of the meandering tube bodies 14 itself can be reduced, and the number of joints to the headers 12 and 13 can be significantly reduced. Further, the dimensional accuracy as in the past is not required. Therefore, unlike the conventional refrigerant condenser 1 which is inferior in assembling workability, the assembling work can be greatly simplified and the manufacturing cost can be greatly reduced.

By the way, in the refrigerant condenser 11 of this type, the refrigerant passage is lengthened so that the condensation distance L (the distance until the refrigerant having entered the inlet of the refrigerant condenser 11 in a superheated gas state is completely liquefied). By increasing the flow rate, the flow rate of the refrigerant can be increased to increase the heat transfer coefficient, while the pressure loss in the pipe increases and the refrigerant pressure decreases, which causes the condensation temperature to decrease. On the contrary, when the condensation distance is reduced, the pressure loss is reduced, but the heat transfer coefficient inside the tube is reduced and the performance is reduced. Therefore, the performance of the refrigerant condenser is determined by the balance between the improvement of the heat transfer coefficient and the pressure loss, and the two influence each other.

Therefore, in the refrigerant condenser using the flat tube 15 having a small conduit area, the present inventors have set the optimal balance between the improvement of the heat transfer rate and the pressure loss and the heat exchange rate. Experiments and studies have been conducted to clarify the optimum condensation distance L, and as a result, the optimum range of the condensation distance L with respect to the equivalent diameter de of the flat tube 15 has been found.

That is, as shown in FIG. 3, the equivalent pipe diameter d
In the case of a small flat tube 15 having a conduit area of e less than 1.15 mm, the condensation distance L (unit m) is L = 0.4 + 1.18 de with respect to the equivalent pipe diameter de (unit mm). It has been experimentally clarified that the heat exchange rate becomes optimal when the range is set to 0.7 + 1.18de (2).

In the meandering tube body 14 as described above, the condensation distance L can be expressed as L = (N + 1) W (3) by using the effective heat exchange width W and the number of times of folding N. . In FIG. 4, the meandering tube body 14 is shown.
The relationship between the number N of times the flat tube 15 is folded back and the condensation distance L is shown. Although FIG. 4 shows only the case where the number N of folding back is an even number, it is a matter of course that the number of folding back can be an odd number by arranging a pair of headers on the same side.

Therefore, from the above equations (2) and (3), the above equation (1) is obtained, and the number of turns N in the meandering tube body 14, the effective heat exchange width W and the equivalent pipe diameter de
The heat exchange rate of the refrigerant condenser 11 could be optimized by setting the above equation (1).

At this time, it is very effective to use the flat tube 15 having the equivalent diameter de in the tube of 1.15 mm or less, but the equivalent diameter de in the flat tube 15 is too small. Even if
On the contrary, since the difficulty of manufacturing the flat tube 15 is increased, it is preferable to use the tube having the equivalent diameter de in the tube of 0.06 mm or more in actual use.

As described above, according to the refrigerant condenser 11 of the present embodiment, the equivalent pipe diameter de (mm) is 0.60 ≦ de ≦ 1.
15 flat tubes 15 in a meandering shape with an effective heat exchange width W
A meandering tube body 14 formed by being diffracted back is connected to a pair of headers 12 and 13, and the number of times of folding N, an effective heat exchange width W (m), and a pipe equivalent diameter d.
Since e is set according to the above formula (1), it is possible to obtain an excellent practical effect that the assembling property is excellent, the manufacturing cost can be reduced, and the heat exchange rate can be designed to be high. Is something that can be done.

[0031]

As is clear from the above description, according to the refrigerant condenser of claim 1 of the present invention, the effective heat exchange width W is formed by the pair of headers forming the refrigerant inlet and outlet and the flat tube. And one or more meandering tube bodies whose both ends are connected to the pair of headers, respectively, and the number of folding times N (integer) of each of the meandering tube bodies and the effective heat The exchange width W (unit: m) is the equivalent pipe diameter de (unit: m) corresponding to the pipe area of the flat tube.
m: However, for de ≦ 1.15), (N + 1) W = 0.4 + 1.18de to 0.7 + 1.1
Since it is set to 8 de, it has an excellent effect that the assembling property is excellent, the manufacturing cost can be reduced, and the heat exchange rate can be designed high. Further, in this case, the inside diameter equivalent to the flat tube de (unit: mm)
Is more effective when 0.60 ≦ de ≦ 1.15 (refrigerant condenser of claim 2).

[Brief description of drawings]

FIG. 1 is a front view schematically showing the entire refrigerant condenser according to an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing the sectional shape of a flat tube.

FIG. 3 is a diagram showing a relationship between an optimum condensation distance and an equivalent diameter of a flat tube in a tube.

FIG. 4 is a diagram illustrating a relationship between the number of times the meandering tube body is folded back and the condensation distance.

FIG. 5 shows a conventional example, and is an exploded perspective view of a refrigerant condenser.

[Explanation of symbols]

In the drawing, 11 is a refrigerant condenser, 12 and 13 are headers, 14
Is a meandering tube body, 15 and 17 are flat tubes, 16
Indicates a corrugated fin.

Claims (2)

[Claims] 1. A pair of headers forming an inlet and an outlet of a refrigerant, and a flat tube folded back in a meandering shape having an effective heat exchange width W, and one or more ends of which are connected to the pair of headers, respectively. A meandering tube body, wherein the number of turns N (integer) of each of the meandering tube bodies and the effective heat exchange width W (unit: m) are equivalent to a pipe equivalent diameter de ( Unit mm: However, de
<1.15), the refrigerant condenser is characterized by the following equation. (N + 1) W = 0.4 + 1.18de to 0.7 + 1.1
8 de 2. The equivalent diameter de in the flat tube (unit:
mm) is 0.60 ≦ de ≦ 1.15. The refrigerant condenser according to claim 1, wherein