JPH0351664A - Heat exchanger - Google Patents

Abstract

PURPOSE:To increase a thermal transferring capability in response to a flow rate of combustion gas and make a uniform heating of refrigerant by a method wherein a fin pitch of any of a plurality of thermal transferring fins is made non-uniform. CONSTITUTION:A natural circulation cycle of a refrigerant heating device to be heated by a burner 12 or the like is divided by a plurality of thermal transferring fins 24 and 25 closely contacted with a thermal transmitting partition wall 13 of a hot gas passage 14 where combustion gas injected from a combustion gas outlet 15 communicates with a combustion chamber II of heat insulation structure. At this time, a fin pitch of any of the thermal transferring fins 25 is changed non-uniformly in response to a flow rate and a temperature of the combustion gas. With such an arrangement, a thermal transferring load becomes constant and the refrigerant is uniformly heated, each of the portions of the refrigerant passage member 17 is uniformly heated and smoothly circulated. As a result, the refrigerant may not be locally overheated and a thermal transfer without any power can be positively carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat exchanger that heats a υ refrigerant using high-temperature gas such as combustion gas and is used in air-conditioning equipment.

BACKGROUND ART A refrigerant heating and heating apparatus as shown in Fig. 6 is known as a system that uses a refrigerant as the fluid to be heated and heats it by combustion gas to evaporate the liquid refrigerant and transport heat by latent heat and perform heating. It is being This refrigerant heating and heating device connects a heat exchanger 1 for combustion gas and refrigerant and a radiator 2 through a sealed pipe 3, and forcibly circulates the refrigerant using a refrigerant conveyor 4 installed in the sealed pipe 3. be. FIG. 7 shows an enlarged view of the heat exchanger 1, in which a plurality of fins 6 are provided on the inner peripheral surface of a cylindrical body 5 extruded from a material such as aluminum and extending in the horizontal direction.
A pipe holding part 7 is provided in the axial direction of the outer peripheral surface of the crossed cylindrical body 5, and a pipe 8 through which a refrigerant flows is embedded in this pipe holding part 7, so that the combustion gas from the burner 9 is transferred to the cylindrical body 5. The refrigerant is flowed horizontally into the interior of the pipe 8 to heat the refrigerant that is sent by the refrigerant conveyor 4 and flows inside the pipe 8.

However, this heating system requires external power to transport the refrigerant, and it is desired to reduce the running costs during heating operation.

Problems to be Solved by the Invention Therefore, in order to reduce running costs during heating operation, it is effective to eliminate external power for transporting refrigerant and transport heat without power. When performing refrigerant heating and heating by non-powered heat transfer, the natural circulation force due to the buoyancy of the gas refrigerant generated when the liquid refrigerant is heated becomes important. However, the conventional refrigerant heating and heating apparatus uses a heat exchanger 1 as shown in FIG. 7, and since the refrigerant flows through a pipe 8 extending in the horizontal direction, it is heated and becomes a gas-liquid two-phase mixture. The gaseous components of the refrigerant do not flow smoothly toward the outlet, causing stagnation of the refrigerant and localized abnormal overheating.Also, since the combustion chamber and heat exchange section are integrated, the amount of heat exchanged depends on the combustion state. There were problems such as non-uniformity, local overheating, thermal decomposition of the refrigerant, and abnormal temperature rise of equipment.

The present invention solves these problems, and enables non-powered transportation to reduce running costs, as well as improve reliability by preventing thermal decomposition of refrigerant and abnormal temperature rise of equipment. The purpose is to achieve this goal.

Tth Means for Solving the Problem In order to solve this problem, the present invention provides a combustion chamber connected to a fuel supply device and having one end communicating with nine burners, and a combustion chamber communicating with the other end of the combustion chamber. The structure includes a combustion gas outlet, a high-temperature gas passage connected to the combustion gas outlet, and a large number of vertical passages provided in the high-temperature gas passage in close contact with a heat transfer partition wall covering the high-temperature gas passage. consisting of a plurality of upper and lower stages of heat transfer fins, a refrigerant passage member that is in close contact with the outer surface of the heat transfer partition, and a heat insulating material that covers the inner surface of the combustion chamber,
Among the plurality of heat transfer fins, the fin pitch of any one of the heat transfer fins is made non-uniform.

This configuration allows the natural refrigerant heating device to be heated with a burner, etc. The ring cycle is divided by a plurality of heat transfer fins that are in close contact with the heat transfer partition wall of the high temperature gas passage through which combustion gas ejected from a combustion gas outlet provided in communication with a combustion chamber having an adiabatic structure passes through. By making the fin pitch of the heat transfer fins non-uniform, the refrigerant can be heated uniformly by changing the pitch of one of the heat transfer fins according to the flow rate and temperature of the combustion gas and keeping the heat transfer load constant. Each part of the refrigerant passage member can be heated uniformly, the refrigerant can be circulated smoothly, and the refrigerant can be reliably transferred without power without being overheated locally, and thermal decomposition of the refrigerant can also be prevented.

EXAMPLE Hereinafter, an example of the present invention will be described based on the drawings.

In Figures 1 to 5, ■ is a combustion chamber that is connected to the fuel supply system but has one end communicating with the fuel tank 2, and this combustion chamber 11 is provided in close contact with the partition wall 13 of #8. The combustion gas outlet 15 and the other end side of the high temperature gas passage member 14 communicate with each other. Note that the high temperature gas passage member 14 has an exhaust pipe 16. In detail, the heat transfer partition 1 is attached to the high temperature gas passage member 14.
3 are combined to form a high temperature gas passage. A refrigerant passage member 17 is provided on the outer surface of the heat transfer partition wall 13 and is thermally connected to the refrigerant passage member 17, and the refrigerant passage member 17 is provided with a large number of passages 18 facing in the vertical direction. An inlet header pipe 19 is provided at the lower end of the refrigerant passage member 17, and an outlet header pipe 20 is provided at the upper end of the refrigerant passage member 17.

An inlet pipe 21 is connected to one end of the inlet header pipe 19, an outlet pipe 22 is connected to one end of the outlet header pipe 20, and each is connected to a refrigerant circuit. At the other end of the inlet header pipe 19 is an oil drain pipe 2 bent downward.
3 is provided. Further, the inlet header pipe 19 and the outlet header pipe 20 communicate with each other through the vertical passage 18. A heat transfer partition wall 13 is provided inside the high temperature gas passage.
The combustion gas outlet 15f is in thermal contact with the inner surface of the combustion gas outlet 15f.
Heat transfer fins 24 and 25 are provided at positions between the upper and lower sides of t, and these are bent into a wave shape. By the way, the combustion chamber 11 has a cylindrical shape, and a heat insulating material 26 is provided on the inner surface of the combustion chamber 11, and the heat transfer fins 25 have a smaller fin pitch than the heat transfer fins 24 and are non-uniform. These heat transfer fins 24, 25 are attached to the heat transfer partition wall 13 and have a large number of passages 24a, 2 facing vertically in an intersecting manner.
5a k, and in a state where the heat transfer fins 24 and 25 are covered with the hot gas passage member 14, the heat transfer fins 2
An exhaust passage 27 is formed which passes through the outer periphery of 4°25 and gathers at the center below the lower heat transfer fins 25. This exhaust passage portion communicates with the exhaust pipe 16.

In the above configuration, the fuel supplied by the fuel supply device is burned in the burner 12, and the high temperature gas generated in the combustion chamber 11 passes through the combustion gas outlet 15 and passes through the passage 24a of the heat transfer fins 24 and 25 inside the high temperature gas passage. e 25a and flows from the exhaust passage n to the exhaust pipe 16. The liquid refrigerant that has entered the inlet header pipe 19 through the inlet pipe 21 is divided into a plurality of vertical passages 18 from the lower part of the refrigerant passage member 17, while heat transfer fins 24 and 25 are connected to the passage 24a.

The heat of the high-temperature gas flowing inside 25a is transferred to the refrigerant passage member 17, and as a result, the passage 18 in the vertical direction of the refrigerant passage member 17
Pour the refrigerant into the lower part near the inlet header pipe 19.
JI#S. There, the liquid refrigerant is heated and begins to vaporize, becoming a gas-liquid two-phase state with bubbles forming in the liquid. The generated bubbles rise in the vertical passage 18 due to the buoyancy effect, and in particular, the combustion gas transfers heat to the refrigerant in the high-temperature gas passage after exiting the combustion gas outlet 15 from the combustion chamber 11, so the temperature of the combustion gas and The flow can be regulated by the combustion gas outlet 15, each part of the refrigerant passage member 17 can be heated uniformly, the refrigerant can be evaporated smoothly and uniformly, the refrigerant can be prevented from being locally overheated, and non-powered heat transfer can be reliably performed. No thermal decomposition occurs. Uniform heating also increases bubble generation by reducing the flow resistance in the passage 18, increasing the bubble upward force, increasing the natural circulation force, and moving the liquid refrigerant that has not yet vaporized to the upper part of the passage 18. A bubble pumping action occurs that transports the refrigerant. By setting the fin pitch of the heat transfer fins 25 smaller than that of the heat transfer fins 24 and making the fin pitch non-uniform, the heat transfer surface @ on the heat transfer fin δ side can be transferred without increasing the passage resistance. It is made larger than the heat fins 24 to increase the heat transfer ability according to the flow rate of combustion gas. That is, the pitch of the fins can be optimally set in accordance with the combustion gas passage resistance of the passage after the combustion gas exits from the combustion chamber 11 through the combustion gas outlet 15 and reaches the exhaust pipe 16 through the high temperature gas passage T. Further, in this embodiment, the pitch of the heat transfer fins 25 on the exhaust pipe 16 side is made smaller than that of the fins 24 over the entire area. As a result, a large amount of combustion gas flows on the heat transfer fin 25 side near the exhaust pipe 16, but the heat transfer area can also be set large. Also, the heat transfer fins 24 having a passage 248°27t for the exhaust pipe 16
Since the passage resistance is large and less combustion gas flows, the heat transfer area is also small, so the total heat exchange rate can be set to be the same as that on the heat transfer fin 25 side, and the temperature of all exhaust combustion gases can be uniformly lowered, resulting in a total heat exchange. This can increase efficiency. Furthermore, by changing the pitch of the fins according to the flow of the refrigerant, the heat transfer performance can be controlled regardless of the flow distribution of the combustion gas.

Since the refrigerant flows mostly near the outlet pipe 22 and has a small flow rate at the end, uniform heat transfer efficiency can be obtained by sequentially decreasing the fin pitch in this part, resulting in high efficiency without overheating. Furthermore, the surface of the heat transfer partition wall 13 other than the portion where the heat transfer fins 24 and 25 are provided also serves as a heat transfer surface, and absorbs heat more efficiently than the high temperature gas flowing in the high temperature gas passage.
The gas-liquid two-phase refrigerant inside is further heated to further increase the natural circulation force. The refrigerant that reaches the upper end of the passageway 18 flows into the outlet header pipe 20 and exits through the outlet pipe n toward a radiator (not shown). In this way, the vertical passage 1
Not only is natural circulation enhanced by uniform heating from the bottom to the top of 8, but the pitch of the heat transfer fins 25 is made smaller at the bottom to further increase the natural circulation force t- by heating even stronger. I can do it. Also, the combustion chamber 11 is connected to the high temperature gas passage member 14? At the same time, the heat transfer partition 13 is attached, and the refrigerant passage member 17 is attached to the heat transfer partition U, so that the heat of the high temperature gas from the combustion chamber 11 is transferred to the heat transfer fins 2.
4.25 to the passage 18 efficiently,
The refrigerant passage member 17 has a multi-tube double-walled structure, which can prevent refrigerant from leaking into the combustion gas section. In addition, since the high-temperature combustion chamber (1) and the passage 18 are completely separated by the high-temperature gas passage formed by the high-temperature gas passage member 14, thermal decomposition and deterioration of the refrigerant due to local overheating do not occur, and the abnormal temperature of the equipment is prevented. It is possible to prevent this from occurring and improve reliability.

Furthermore, the refrigerant passage member 17 is made of a multi-tube flat extruded tube made of aluminum having a large number of passages inside, and the heat transfer fins 24 and 25 are made of band-shaped aluminum plates bent in a wave shape. The thermal partition wall 13 is assembled as a plating sheet in which the front and back sides of an aluminum core material are clad with brazing material in advance, and by integrally plating at the same time, the pitch of the fins can be easily varied and thermal communication can be achieved, resulting in a low contact thermal resistance. A lightweight, low-cost heat exchanger with excellent heat transfer performance can be obtained.

In addition, one side of the aluminum core material of the high-temperature gas passage member 14 is made of a brazing sheet clad with a brazing material in advance, and the heat transfer fins 24 and 25 are integrated with the heat transfer fins 24 and 25 by brazing, thereby transferring heat from the combustion chamber 11. The heat is transferred to the passage 18 through the heat transfer fins 24 and 25 with high heat exchange efficiency, making it possible to increase efficiency and make the equipment more compact.

By making the high temperature gas passage member 14 aluminum and integrally glazing it with the heat transfer partition wall 13, it is a simple structure and can maintain airtightness, preventing exhaust gas from leaking.
It is highly safe.

Also, oil from the compressor is always dissolved in the refrigerant, and when the refrigerant is vaporized in the heater, the oil gradually accumulates. When a large amount of oil accumulates, its viscosity and low heat conductivity hinder the vaporization and circulation of the refrigerant. Therefore, an oil drain pipe 23 is provided which is connected to the inlet header pipe 19 at the bottom of the passage 18 of the refrigerant passage member 17.If oil accumulates in the heater, the oil will be drained together with the refrigerant through the oil drain pipe. 23, ensuring that oil is removed from the heater and maintaining uniform circulation of the refrigerant to eliminate thermal decomposition of the refrigerant due to local overheating.
C reliability can be improved.

Effects of the Invention As described above, according to the present invention, the t
a combustion chamber with one end communicating with the burner; a combustion gas outlet communicating with the other end of the combustion chamber; a high-temperature gas passage communicating with the combustion gas outlet; A plurality of upper and lower heat transfer fins each having a plurality of passages in the vertical direction, which are provided in close contact with a heat transfer partition wall covering the high temperature passage within the passage, and a refrigerant passage member, which is provided in close contact with the outer surface of the heat transfer partition wall. , and a heat insulating material covering the inner surface of the combustion chamber, and the fin pitch of any of the heat transfer fins among the plurality of heat transfer fins is non-uniform, and the following effects are obtained.

In other words, since the fin pitch of any one of the heat transfer fins is nonuniform, the heat transfer area on the heat transfer fin side is larger than that of the other heat transfer fins without increasing the passage resistance, and the combustion gas is The heat transfer capacity increases depending on the flow rate. That is, the pitch of the fins can be optimally set according to the resistance with which the combustion gas passes through the high-temperature gas passage after exiting the combustion gas outlet from the combustion chamber. Furthermore, by changing the pitch of the fins according to the flow of the refrigerant, the heat transfer ability can be distributed, and the heat exchange performance can be controlled regardless of the flow distribution of the combustion gas. Further, heat transfer fins of the number tvi are provided in close contact with the heat transfer partition wall in the high temperature gas passage through which combustion gas ejected from a combustion gas outlet provided in communication with a combustion chamber having an adiabatic structure passes;
A heat exchanger configured with a heat transfer partition wall and a refrigerant passage member can equalize the temperature and flow of combustion gas, uniformly heat all parts of the refrigerant passage member, circulate the refrigerant smoothly, and locally superheat the refrigerant. It is possible to reliably carry out non-powered heat transfer without any problems, and also to prevent thermal decomposition of the refrigerant. Uniform heating reduces the flow resistance inside the refrigerant passage member, which increases bubble generation, strengthens the external force of the bubble bubbles, strengthens the natural circulation force, increases heat exchange efficiency, and makes equipment more compact. Furthermore, by preventing local abnormal overheating of the refrigerant through uniform heating, it is possible to improve reliability by preventing abnormal temperature rises in equipment. Furthermore, since non-powered heat transfer is possible, running costs can be reduced.

[Brief explanation of drawings]

Figures 1 to 5 show one embodiment of the present invention.
Figure 2 is a longitudinal cross-sectional view of the heat exchanger, Figure 2 is a cross-sectional view of the refrigerant passage member, Figure 3 is an exploded perspective view of the heat exchanger, Figure 4 is a cross-sectional view of the lower heat transfer fins, Figure 5 is a diagram of the internal configuration of the high-temperature gas passage, Figure 6 is a circuit diagram of a conventional refrigerant heating system,
FIG. 7 is a perspective view of a conventional heat exchanger. DESCRIPTION OF SYMBOLS 11... Combustion chamber, 12... Burner, 13... Heat transfer partition, 14... High temperature gas passage member, 15... Combustion gas outlet, 16... Exhaust pipe, 17... Refrigerant passage member,
18... Passage, 19... Inlet header pipe, 20...
・Outlet header pipe, 24.25...Heat transfer fin, 24
a e 25a...Aisle, ah...insulation material.

Claims (1)

[Claims] 1. A combustion chamber with one end communicating with a burner connected to a fuel supply device, a combustion gas outlet communicating with the other end of the combustion chamber, and a high temperature combustion chamber communicating with the combustion gas outlet. a gas passage, a plurality of upper and lower stages of heat transfer fins provided in the high temperature gas passage in close contact with a heat transfer partition wall covering the high temperature gas passage and having a large number of passages in the vertical direction; A heat exchanger comprising a refrigerant passage member and a heat insulating material covering an inner surface of the combustion chamber, and in which one of the plurality of heat transfer fins has an uneven fin pitch.