JPH10220921A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger in which refrigerant is heated by discharged gas of high temperature generated under combustion so as to be utilized in a heating device and a heat exchanging operation is carried out in a high efficiency to prevent a local overheating of equipment and thermal decomposition of refrigerant. SOLUTION: This heat exchanger is operated such that a large amount of combustion discharged gas is flowed at a downstream side of a porous pipe 11 where a large amount of liquid refrigerant is distributed by a resistor plate 16 and a resistor plate 17 controlling a distribution of flow rate of combustion discharged gas in horizontal and vertical directions of high temperature combustion gas flowing in heat transfer fins 8, 9, wherein the refrigerant becomes two phases of gas and liquid, the combustion discharged gas is divided to flow in upper and lower directions above the porous pipe 11 having a less amount of distribution of the liquid refrigerant, a large amount of combustion discharged gas is flowed in a horizontal direction as it approaches an inlet or outlet of the porous pipe 11 for refrigerant where a large amount of passing refrigerant is present, thereby local overheating of the heat transfer fins 8, 9 and the porous pipe 11 is eliminated, and then a thermal decomposition of refrigerant or an abnormal increasing in temperature of the device is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger for heating a refrigerant with high temperature exhaust gas generated by combustion and utilizing the refrigerant in a heating device.

[0002]

2. Description of the Related Art Conventionally, a heat exchanger for heating a refrigerant by combustion to evaporate and evaporate a liquid refrigerant and carry heat by latent heat for heating is described in Japanese Patent Publication No. 7-18595. Was common. This heat exchanger is shown in FIG.
As shown in (a) and (b), reference numeral 3 denotes a combustion chamber having one end connected to a burner 2 connected to the fuel supply device 1, and the combustion chamber 3 is a combustion exhaust gas provided in close contact with the heat transfer partition 10. The other end is connected to the passage member 5. The flue gas passage member 5 has an exhaust pipe 6, and the flue gas passage member 5 is combined with a heat transfer partition 10 to form a flue gas passage. A heat transfer partition 10 is provided inside the flue gas passage.
The upper and lower two heat transfer fins 8 and 9 are provided so as to closely contact with each other and form a combustion exhaust gas inlet 7.

[0003] Further, as shown in FIG.
The heat transfer fins 8 and 9 form a large number of passages extending in the vertical direction when mounted on the heat transfer partition 10.
The exhaust passage 15 is formed so as to pass through the outer circumferences of the heat transfer fins 8 and 9 and to gather at the upper center of the upper heat transfer fin 8 in a state where the heat transfer fins 8 are covered with the combustion exhaust gas passage member 5. The length of the passage 8a of the heat transfer fin 8 is longer than the length of the passage 9a of the heat transfer fin 9. A heat-coupled multi-hole tube 11 is provided on the outer surface of the heat transfer partition 10, and the multi-hole tube 11 is provided with a large number of passages 12 extending vertically. A refrigerant inlet header tube 13 is provided at a lower end of the multi-hole tube 11, and a refrigerant outlet header tube 14 is provided at an upper end of the multi-hole tube 11.

[0004] The fuel supplied from the fuel supply device 1 is burned by the burner 2, and the flue gas generated in the combustion chamber 3 passes through the flue gas inlet 7 as shown by the arrow in FIG. The gas flows from the exhaust passage 15 to the exhaust pipe 6 through the passages 8 a and 9 a of 8 and 9. The liquid refrigerant entering the refrigerant inlet header pipe 13 is diverted from the lower part of the multi-hole pipe 11 to a number of vertical passages 12, while the heat transfer fins 8, 9 generate heat of the high-temperature flue gas flowing through the passages 8 a, 9 a. Is transferred to the multi-hole tube 11, thereby heating the refrigerant in the passage 12.
Then, the heated liquid refrigerant starts vaporizing and evaporating, and enters a gas-liquid two-phase state in which bubbles are generated in the liquid. The generated bubbles rise in the vertical passage 12 due to the buoyancy effect, and flow out to the refrigerant outlet header tube 14 above the upper end of the multi-hole tube 11.

[0005]

However, the conventional structure described above has a means for optimizing the flue gas in the horizontal direction only by optimizing the amount of flue gas in the vertical direction by the length of the heat transfer fins 8 and 9. Therefore, in the configuration of the refrigerant passage of the multi-hole tube 11 having the header tube, there is a problem that depending on the position of the exhaust port 6, a locally overheated portion is generated in the multi-hole tube 11 to cause thermal decomposition of the refrigerant and abnormal temperature rise of the equipment. .

The present invention solves the above-mentioned problems, and optimizes the amount of flue gas in the vertical and horizontal directions regardless of the position of the exhaust port 6 to prevent thermal decomposition of refrigerant and abnormal rise in temperature of equipment. It is intended to improve the reliability of the equipment.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises a combustion exhaust gas passage member having a burner at one end and an exhaust pipe at the other end of a substantially horizontal combustion cylinder, and a heat transfer partition. A plurality of heat transfer fins having a combustion exhaust gas passage having a combustion exhaust gas inlet serving as a combustion exhaust gas inflow portion on the combustion chamber side of the heat transfer partition. On the opposite side of the combustion chamber, a multi-hole pipe having a plurality of vertically extending refrigerant passages which are in close contact with the heat transfer fins and the heat transfer partition, and a refrigerant inlet header pipe having one end closed at a lower end of the multi-hole pipe. The upper end is provided with a refrigerant outlet header tube having one end closed on the same side as the refrigerant inlet header tube, and the upper and lower combustion exhaust gas outflow portions of the plurality of heat transfer fins are provided with the refrigerant outlet header tube and the refrigerant inlet header tube. Upper and lower flue gas closer to the closed side Passage area of the exit portion is configured to include a resistive plate having a shape which is small.

According to the above invention, the passage resistance of the upper heat transfer fin and the passage resistance of the upper combustion exhaust gas outlet are larger than the passage resistance of the lower heat transfer fin, that is, the passage resistance of the lower combustion exhaust gas outlet. A large amount of flue gas flows through the heat transfer fins on the lower side of the multi-hole tube where a large amount of liquid refrigerant is distributed, and the refrigerant becomes a gas-liquid two-phase state. The heat transfer fins and the multi-hole tube can be effectively heated in a well-balanced manner in the vertical direction so that the heat exchange efficiency is improved.

Further, in the horizontal direction, the flow of the combustion exhaust gas is increased toward the refrigerant inlet / outlet side of the multi-hole tube where the passage amount of the refrigerant is small as a result of the small passage resistance, so that the local overheating of the heat transfer fins is eliminated and the thermal decomposition of the refrigerant and the equipment Abnormal temperature rise can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a combustion chamber comprising a combustion gas passage member having a burner at one end and an exhaust pipe at the other end of a substantially horizontal combustion cylinder, and a heat transfer partition. A plurality of heat transfer fins having a flue gas passage having a flue gas inlet serving as a flue gas inflow portion are provided on the combustion chamber side of the partition wall, and the heat transfer fin is provided on a side of the heat transfer fin opposite to the combustion chamber. And a multi-hole pipe having a plurality of vertically extending refrigerant passages which are in close contact with the heat transfer partition, a refrigerant inlet header pipe having one end closed at a lower end of the multi-hole pipe, and a refrigerant inlet header pipe at an upper end. A refrigerant outlet header pipe having one end closed on the same side is provided, and the upper and lower flue gas outflow portions of the plurality of heat transfer fins are provided with the upper and lower flue gas outflow portions closer to the closed side of the refrigerant outlet header tube and the refrigerant inlet header tube. The passage area is small. It has become equipped with resistive plate configuration.

The resistance plate has a configuration in which the passage area of the lower combustion exhaust gas outlet is larger than the passage area of the upper combustion exhaust gas outlet.

A gap is provided between the upper and lower combustion exhaust gas outflow portions of the heat transfer fins and the resistance plate, and the gap is larger in the lower part than in the upper part.

Further, the resistance plate has a plurality of holes formed in the plate and is closely joined to the upper and lower combustion exhaust gas outflow portions of the heat transfer fins, and the plurality of holes of the resistance plate serve as upper and lower combustion exhaust gas outflow passages. .

The heat transfer fins are made of extruded material of a good heat transfer material having a vertical flue gas passage, and the flue gas passage from the lower flue gas inlet to the lower flue gas outlet is the upper flue gas outlet. The configuration is shorter than the flue gas passage from the flue gas inlet to the upper flue gas outflow portion.

Since the resistance plate is shaped such that the area of the upper and lower combustion exhaust gas outflow portions of the heat transfer fins becomes smaller as the resistance outlet plate and the refrigerant inlet header tube become closer to the closed side.
In the horizontal direction, the larger the amount of refrigerant passing through the multi-hole tube, the more the combustion exhaust gas flows to the heat transfer fin side, eliminating local overheating of the heat transfer fins and preventing thermal decomposition of the refrigerant and abnormal temperature rise of equipment, In addition, the vertical passage of the combustion passage is such that the gap between the upper and lower combustion exhaust gas outlets of the heat transfer fins and the resistance plate is larger in the lower part than in the upper part. Heat transfer fins are used to divide the combustion exhaust gas in the vertical direction so that the combustion exhaust gas flows more in the upper part of the multi-hole pipe in which the refrigerant flows into a gas-liquid two-phase state and the distribution of the liquid refrigerant is less than in the lower part. Since the multi-hole tube can be effectively heated in the vertical direction in a well-balanced manner, the vertical and horizontal combustion can be optimized regardless of the position of the exhaust port.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same functional components as in FIGS. 6 and 7 of the conventional example are denoted by the same reference numerals.

Embodiment 1 FIGS. 1A and 1B are cross-sectional views of a heat exchanger according to Embodiment 1 of the present invention. In FIG. 1, 3
Is a combustion chamber provided at one end thereof in communication with a burner 2 connected to the fuel supply device 1. The combustion chamber 3 is integrated with a combustion exhaust gas passage member 5 provided in close contact with a heat transfer partition 10. I have. As shown in FIGS. 2A, 2B and 2C, the flue gas passage member 5 has an exhaust pipe 6. Specifically, the combustion exhaust gas passage member 5 is combined with the heat transfer partition 10 to form a combustion exhaust gas passage. A multi-hole tube 11 that is closely bonded to the outside of the heat transfer partition 10 is provided, and the multi-hole tube 11 is provided with a large number of passages 12 that penetrate vertically. The lower end of the multi-hole tube 11 is provided with a refrigerant inlet header tube 13 whose one end is closed, and the upper end of the multi-hole tube 11 is a refrigerant whose one end is closed in the same direction as the closed one end of the refrigerant inlet header tube 13. An outlet header tube 14 is provided.

The refrigerant ports 13a, 14a of the refrigerant port header tubes 13, 14 are connected to a refrigerant circuit, respectively. The refrigerant inlet header tube 13 and the refrigerant outlet header tube 14 are in communication with each other through a vertical passage 11. Inside the flue gas passage, heat transfer fins 8 and 9 are tightly joined to the inner surface of the heat transfer partition 10. Incidentally, the combustion chamber 3 is cylindrical, and a heat insulating material 4 is provided on an inner surface thereof.

As shown in FIG. 2, the heat transfer fins 8 and 9 form a large number of heat transfer fin passages 8a and 9a which are vertically oriented in a state of being closely bonded to the heat transfer partition 10. 9 is covered with the flue gas passage member 5 and passes through the outer circumferences of the heat transfer fins 8 and 9 and the flue gas inlet 7
The exhaust passage 15 is formed so as to be gathered to the left of the exhaust passage. The exhaust passage 15 communicates with the exhaust pipe 6. A resistance plate A16 and a resistance plate B17 are provided on the inner surface of the heat transfer partition 10 to regulate the amount of combustion exhaust gas passing through the outlets of the heat transfer fin passages 8a and 9a. The heat transfer fin 8 is provided with a heat transfer fin thick portion 20, and the heat transfer fin 8 is also provided with a multi-hole tube thick portion 21 which is vertically continuous at a corresponding position of the multi-hole tube 11. Thick part 20
A temperature detection unit 18 is provided above the heat transfer fins 8, and a temperature detection sensor 19 is attached so as to penetrate the temperature detection unit 18 of the heat transfer fin 8 and reach the multi-hole tube thick portion 21.

Next, the operation and operation will be described. In the above configuration, the fuel supplied from the fuel supply device 1 is burned by the burner 2, and the high-temperature flue gas generated in the combustion chamber 3 passes through the flue gas inlet 7 and is transferred to the heat transfer fins 8 and 9 inside the flue gas passage. The gas flows from the exhaust passage 15 to the exhaust pipe 6 through the heat fin passages 8a and 9a. The liquid refrigerant that has entered the refrigerant inlet header tube 13 is diverted from the lower part of the multi-hole tube 11 into a number of vertical passages 12, while the heat transfer fins 8, 9 are used to separate the combustion exhaust gas flowing through the heat transfer fin passages 8 a, 9 a. Heat to multi-hole tube 11
As a result, the refrigerant in the vertical passage 12 of the multi-hole tube 11 is sequentially heated from the lower portion near the refrigerant inlet header tube 13.

Then, the heated liquid refrigerant starts vaporizing and evaporating, and enters a gas-liquid two-phase state in which bubbles are generated in the liquid. The generated bubbles rise in the vertical passage 12 due to the buoyancy effect,
The refrigerant flows into the refrigerant outlet header tube 14 with the liquid refrigerant. By making the shape of the resistance plate A16 a shape in which the combustion exhaust gas is difficult to flow with respect to the resistance plate B17, a large amount of the combustion exhaust gas flows under the multi-hole tube 11 where a large amount of the liquid refrigerant is distributed, and the refrigerant becomes a gas-liquid two-phase state. On the upper side of the multi-hole tube 11 where the distribution of the refrigerant is small, the flue gas can be divided vertically so that the flue gas flows less than on the lower side.

Thus, the heat transfer fins 8 and 9 are effectively heated, and the refrigerant in the multi-hole tube 11 is also efficiently heated in the vertical direction. As a result, heat can be exchanged efficiently without local overheating of the heat transfer fins 8, 9 and the multi-hole tube 11. Also, no thermal decomposition of the refrigerant occurs.

Further, the flow rate distribution of the combustion exhaust gas flowing into the heat transfer fins 8 and 9 in the horizontal direction by the resistance plates A16 and B17 is determined by the refrigerant inlet / outlet 1 of the multi-hole tube 11 through which a large amount of refrigerant passes.
3a, the exhaust gas is controlled to flow more toward the refrigerant outlet 14a, and the heat transfer fins 8, 9 and the multi-hole tube 11 are efficiently heated and exchanged heat even in the horizontal direction.

In the present embodiment, as shown in FIG. 2, the flow rate of the refrigerant in the horizontal direction of the multi-hole tube 11 tends to be large at the refrigerant inlet 13a and the refrigerant outlet 14a having a small flow path resistance. The flow rate distribution of the combustion exhaust gas in the horizontal direction in 9 is also set by the resistance plates A16 and B17 so that the refrigerant inlet 13a and the refrigerant outlet 14a side are increased.

In this embodiment, as shown in FIG.
6. If the shape of the resistance plate B17 is high in the X direction of the coordinate axis of the flue gas discharge portion of the heat transfer fins 8 and 9, the resistance is large, and if the shape is low, the resistance is small. If it is desired to diverge a large amount, the height of the resistance plate 16 in the coordinate axis X direction may be higher than the height of the resistance plate 17. In the horizontal direction, the resistance plate A16 and the resistance plate B are controlled in such a manner that the combustion exhaust gas is controlled to flow toward the refrigerant inlet / outlet 13a, 14a side of the multi-hole tube 11 where the refrigerant passage amount is large.
It is assumed that the height in the coordinate axis X direction decreases stepwise as the shape 17 moves in the coordinate axis Y direction.

In this embodiment, the exhaust pipe 6 is connected to the heat transfer fins 8 and 9 by the refrigerant inlet 1 to make the equipment compact in the vertical direction.
3a and the refrigerant outlet 14a are located on opposite sides. However, since the flow distribution of the combustion exhaust gas can be controlled by the shapes of the resistance plates A16 and B17, the position of the exhaust pipe 6 is changed to the heat transfer fins 8, 9 can be set freely.

(Embodiment 2) FIG. 3 is a diagram showing a positional relationship between a heat transfer fin and a resistance plate according to Embodiment 2 of the present invention. The components having the same reference numerals as those in the first embodiment have the same structure, and the description will be omitted.

The difference from the first embodiment is that the vertical flow of the combustion exhaust gas in the heat transfer fins 8 is controlled by the size of the gap between the resistance plates A16 and B17 and the heat transfer fins 9 in the coordinate axis Z direction. is there.

Next, the operation and operation will be described. As described in the first embodiment, since the refrigerant in the multi-hole officer 11 has a large amount of liquid refrigerant distributed below, it is necessary to diverge a large amount of high-temperature combustion exhaust gas downward in the heat transfer fins 8. In this case, in the first embodiment, the resistance of the upper combustion exhaust gas outflow portion of the heat transfer fin 9 is made larger than the resistance of the lower combustion exhaust gas outflow portion by making the height of the resistance plate A16 in the coordinate axis X direction higher than the height of the resistance plate B. As a result, in the present embodiment, as shown in the figure, the lower flue gas outflow portion of the heat transfer fin 9 and the Z-direction gap between the resistance plate 17 are separated from the upper flue gas outflow portion. By making the gap larger than the gap in the Z direction between the fuel gas and the resistance plate 16, the combustion exhaust gas is largely diverted downward.

Thus, the heat transfer fins 8 and 9 are effectively heated, and the refrigerant in the multi-hole tube 11 is also efficiently heated in the vertical direction. As a result, heat can be exchanged efficiently without local overheating of the heat transfer fins 8, 9 and the multi-hole tube 11. Also, no thermal decomposition of the refrigerant occurs.

(Embodiment 3) FIG. 4 is a view showing a heat transfer fin and a resistance plate according to Embodiment 3 of the present invention. The components having the same reference numerals as those in the first embodiment have the same structure, and the description will be omitted.

The difference from the first embodiment is that the heat transfer fins 8 and 9
As shown in FIG. 4, the vertical distribution and horizontal flow distribution of the combustion exhaust gas in the inside are made by forming a hole in a single plate having a resistance plate shape, and the passage resistance of the combustion exhaust gas is determined by the shape and area of the hole. It is to control.

Next, the operation and function will be described. The flow rate of the flue gas in the horizontal direction in the heat transfer fins 8 and 9 is controlled by increasing the width of the hole as it proceeds in the Y direction, and the flow rate of the flue gas in the vertical direction is controlled. With regard to the flow division balance, by making the hole area of the resistance plate 17 larger than the hole area of the resistance plate 16, a large amount of the combustion exhaust gas is diverted downward.

As a result, the heat transfer fins 8 and 9 are effectively heated, and the refrigerant in the multi-hole tube 11 is also efficiently heated in the vertical direction. As a result, heat can be exchanged efficiently without local overheating of the heat transfer fins 8, 9 and the multi-hole tube 11. Also, no thermal decomposition of the refrigerant occurs.

Further, the flow rate distribution of the flue gas in the horizontal direction is controlled such that the flue gas flows more toward the refrigerant inlet / outlet 13a and the refrigerant outlet 14a of the multi-hole tube 11 having a larger amount of refrigerant passing therethrough. The multi-hole tube 11 is efficiently heated and heat exchanged even in the horizontal direction.

Embodiment 4 FIG. 5 is a front view of a heat transfer fin according to Embodiment 3 of the present invention. The components having the same reference numerals as those in the first embodiment have the same structure, and the description will be omitted.

The difference from the first embodiment is that the heat transfer fins 8 and 9
Is an integrated aluminum extruded material, in which the combustion passage from the lower end of the flue gas inlet 7 to the lower flue gas outlet is shorter than the combustion passage from the upper end of the flue gas inlet 7 to the upper flue gas outlet. is there.

Next, the operation and operation will be described. The length of the heat transfer fin passages 8a, 9a of the heat transfer fins 8, 9 is
The heat transfer fin passage 8a is set longer than the heat transfer fin passage 9a. Therefore, the branch flow of the combustion exhaust gas in the heat transfer fins 8 and 9 increases in the downward direction where the passage resistance is small.

As a result, the heat transfer fins 8 and 9 are effectively heated, and the refrigerant in the multi-hole tube 11 is also efficiently heated in the vertical direction. As a result, heat can be exchanged efficiently without local overheating of the heat transfer fins 8, 9 and the multi-hole tube 11. Also, no thermal decomposition of the refrigerant occurs.

[0040]

As described above, according to the present invention, a burner is provided at one end of a substantially horizontal combustion cylinder, and a combustion exhaust gas passage member is provided at the other end, and a combustion chamber is constituted by the heat transfer partition, the combustion cylinder, and the burner. A heat transfer fin having a large number of combustion exhaust gas passages on the combustion chamber side of the heat transfer partition, and a multi-hole pipe having a plurality of refrigerant passages on the opposite side of the combustion chamber of the heat transfer partition are closely joined to form a multi-hole pipe. A refrigerant inlet header tube is provided at a lower end of the tube, and a refrigerant outlet header tube is provided at an upper end, and a resistance plate is provided at the heat transfer upper and lower flue gas outflow portion, and the resistance plate is a refrigerant outlet header tube and a refrigerant inlet header tube. The closer to the closed side, the smaller the area of the upper and lower combustion flue gas outflow area of the heat transfer fins on the refrigerant inlet / outlet side. Heat transfer fin station by flowing a lot Overheating is eliminated, preventing thermal decomposition of the refrigerant and abnormal rise in temperature of the equipment.In addition, the upper and lower combustion passages have a larger gap between the upper and lower combustion exhaust gas outflow portions of the heat transfer fins and the resistance plate in the lower part than in the upper part. Therefore, a large amount of combustion exhaust gas flows under the multi-hole pipe where a large amount of liquid refrigerant is distributed, and the refrigerant becomes a gas-liquid two-phase state, and the combustion exhaust gas flows over the multi-hole pipe where the distribution of the liquid refrigerant is small. Dividing the flue gas in the vertical direction so that it flows less than the lower side, the heat transfer fins and the multi-hole tube can be effectively heated in a balanced manner in the vertical direction. This has the effect of optimizing the horizontal direction and improving the reliability of the device.

[Brief description of the drawings]

FIG. 1A is a sectional view of a heat exchanger according to a first embodiment of the present invention. FIG. 1B is a sectional view of the same heat exchanger taken along line AA.

FIG. 2 (a) is a structural diagram of the inside of the flue gas passage, (b) a flow distribution diagram of the flue gas and the refrigerant corresponding to the essential part of the flue gas passage, and (c) a side view of the principal part of the heat exchanger.

FIG. 3 is a diagram showing a positional relationship between a heat transfer fin and a resistance plate according to the second embodiment.

FIG. 4A is a front view of the resistance plate and the heat transfer fin according to the third embodiment. FIG.

FIG. 5 is a front view of a heat transfer fin according to a fourth embodiment.

6A is a cross-sectional view of a conventional heat exchanger. FIG. 6B is a cross-sectional view of the heat exchanger taken along line AA.

FIG. 7 is a configuration diagram of the inside of a flue gas passage of a conventional example.

[Explanation of symbols]

 Reference Signs List 2 burner 3 combustion chamber 5 flue gas passage member 6 exhaust pipe 7 flue gas inlet 8 heat transfer fin 9 heat transfer fin 10 heat transfer partition 11 multi-hole pipe 12 refrigerant passage 13 refrigerant inlet header pipe 14 refrigerant outlet header pipe

Continued on the front page (72) Inventor Hideshi Ochiai 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A combustion chamber comprising a combustion exhaust gas passage member having a burner at one end and an exhaust pipe at the other end, and a heat transfer partition, and a heat transfer partition, the combustion tube being substantially horizontal. Has a plurality of heat transfer fins having a flue gas passage having a flue gas inlet serving as a flue gas inflow portion, and the heat transfer fin and the heat transfer partition are provided on a side of the heat transfer fin opposite to the combustion chamber. A multi-hole pipe having a plurality of vertically extending refrigerant passages that are in close contact with a refrigerant inlet header pipe having one end closed at the lower end of the multi-hole pipe, and one end on the same side as the refrigerant inlet header pipe at the upper end. A closed refrigerant outlet header pipe is provided, and the upper and lower flue gas outflow portion of the plurality of heat transfer fins has a smaller passage area of the upper and lower flue gas outflow portion as approaching the closed side of the refrigerant outlet header tube and the refrigerant inlet header tube. Equipped with a resistor plate in the shape of Exchanger. 2. The heat exchanger according to claim 1, wherein the resistance plate has a shape in which a passage area of the lower combustion exhaust gas outlet is larger than a passage area of the upper combustion exhaust gas outlet. 3. The heat exchanger according to claim 1, wherein a gap is provided between the upper and lower combustion exhaust gas outflow portions of the heat transfer fins and the resistance plate, and the gap is larger at a lower portion than at an upper portion. 4. A resistance plate, wherein a plurality of holes are provided in the plate, and the resistance plate is closely joined to a vertical flue gas outflow portion of a heat transfer fin, and the plurality of holes of the resistance plate form a vertical flue gas outflow passage. The heat exchanger according to 1. 5. The heat transfer fin comprises an extruded material of a good heat transfer material having a vertical flue gas passage, and a flue gas passage from a lower flue gas inlet to a lower flue gas outflow portion has an upper flue gas passage. 2. A structure in which the length of the flue gas passage from the flue gas inlet to the upper flue gas outflow portion is shorter.
The heat exchanger as described.