JP2001074327A - Heat exchanger for stirling refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger for a Stirling refrigerating machine excellent in heat exchange efficiency, pressure durability and refrigeration efficiency and suitable for an air conditioning apparatus adopting air conditioning air as a fluid for heat exchange by providing a relatively large heating surface area. SOLUTION: The inventional aims at adopting a fin-and-flat tube heat exchanger instead of a conventional shell-and-tube type. In a Stirling refrigerating machine by a Stirling cycle where reciprocating motion of a working gas operates refrigeration, the heat exchanger for the Stirling refrigerating machine for performing heat exchange between a working gas and a fluid to be heat exchanged includes a working gas flow route for flowing the working gas, flat tubes 22 having wide width and capable of keeping in contact with the fluid, fins 23 provided on the flat tubes 22, and flanges 25 capable of fixing the flat tubes 22.

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 a Stirling refrigerating machine, and more particularly to a refrigerating machine utilizing a Stirling cycle, which is capable of improving the refrigerating efficiency for mounting on a vehicle. It relates to a heat exchanger.

[0002]

2. Description of the Related Art Conventionally, a Stirling refrigerator using a Stirling cycle has been used as a cryogenic refrigerator. The configuration of the Stirling refrigerator and the heat exchanger for the Stirling refrigerator will be outlined based on FIGS. 3 and 4. FIG. 3 is a conceptual diagram of the structure of a general Stirling refrigerator 1. The Stirling refrigerator 1 includes a compression cylinder 3, a compression piston 4, and a compression piston 4 that constitute a high-temperature compression chamber 2 for a working gas such as helium gas. An expansion cylinder 6 forming a low-temperature expansion chamber 5 for gas and an expansion piston 7
A radiator 8 (high-temperature side heat exchanger), a heat absorber 9 (low-temperature side heat exchanger), a regenerator 10 (heat accumulator), a crankshaft 11 (drive mechanism), a working gas pipe 12, Having.

[0003] The compression piston 4 reciprocates in the compression cylinder 3, the expansion piston 7 reciprocates in the expansion cylinder 6, and the compression piston 4 and the expansion piston 7 have a predetermined phase difference from each other by a crankshaft 11. θ (for example, 90 degrees).

The regenerator 10 is filled with a material having a heat storage (cool storage) function, and forms a thermal wall between the high-temperature side heat exchanger 8 and the low-temperature side heat exchanger 9. The working gas pipe 12
The compression chamber 2, the expansion chamber 5, and the regenerator 10 are connected, and these constitute one closed space for working gas.

[0005] In the Stirling refrigerator 1, one round of the crankshaft 11 is divided into four strokes. That is, the isothermal compression stroke, the equal volume shift process, the isothermal expansion process, and the equal volume shift process are repeated, and the working gas reciprocates between the compression chamber 2 and the expansion chamber 5 via the regenerator 10 to generate a refrigeration capacity. The Stirling refrigerator 1 is used for cooling an infrared detector, for example.

However, the heat exchanger of the Stirling refrigerator 1 (radiator 8 and heat absorber 9, hereinafter referred to as "heat exchanger 8 for Stirling refrigerator") has conventionally been a shell and tube type heat exchanger. Containers and the like are widely used, and are mainly used for heating or cooling a liquid such as water. FIG. 4 is a partially cutaway perspective view of the shell-and-tube type heat exchanger 8 for a Stirling refrigerator.
Is a cylindrical shell 13 and a pair of upper and lower flanges 14
And a plurality of tubes 15 inside.

A water inlet 16 formed in one of the shells 13
The heat exchange fluid (e.g., water) flows through the water outlet portion 17 to exchange heat with a refrigerant or a working gas (e.g., helium gas) flowing through the tube 15 to heat or cool the water.

In order to use the Stirling refrigerator 1 for an air conditioner, air (air conditioning air) is used by using a liquid such as water cooled by the shell-and-tube type Stirling refrigerator heat exchanger 8. In the method of cooling (1), the surface area in contact with the liquid in the tube 15 is not so large, and the efficiency of cooling air or the like is low.
That is, a primary heat exchanger for exchanging heat between the refrigerant and water and a secondary heat exchanger for exchanging heat between the water and air are required, and further, a mechanism such as a pump for pumping water to the primary heat exchanger is provided. It is necessary, and there is a problem that the refrigeration efficiency is reduced for an air conditioner.

Thus, in order to perform a highly efficient air-conditioning operation in the Stirling refrigerator 1, a heat exchanger that directly cools the air by the Stirling refrigerator 1 is advantageous. When trying to cool the air using the refrigerator heat exchanger 8, there is a problem that a sufficient heat transfer efficiency cannot be expected because a sufficient heat transfer area cannot be obtained on the air side.

Furthermore, in order for the Stirling refrigerator 1 to achieve such a refrigerating capacity, it is necessary to increase the working gas injection pressure.
However, there is a problem that enhancement of pressure resistance is required.

[0011] Examples of the Stirling refrigerator include JP-A-9-49666 and JP-A-9-53891.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a heat exchanger for a Stirling refrigerating machine having good refrigeration efficiency.

Another object of the present invention is to provide a heat exchanger for a Stirling refrigerator having a relatively large heat transfer area and good heat conversion efficiency.

Another object of the present invention is to provide a heat exchanger for a Stirling refrigerator having high pressure resistance.

Another object of the present invention is to provide a heat exchanger for a Stirling refrigerator suitable for an air conditioner, employing conditioned air as a heat exchange fluid.

[0016]

That is, the present invention focuses on the use of a fin and flat tube type heat exchanger instead of the conventional shell and tube type heat exchanger. In a Stirling refrigerator by a Stirling cycle performing a refrigeration operation, a Stirling refrigerator heat exchanger that performs heat exchange between the working gas and the fluid to be heat-exchanged, wherein a working gas flow path through which the working gas flows is provided. A heat exchange for a Stirling refrigerator, comprising: a wide flat tube having a flat tube that can be brought into contact with the fluid to be heat-exchanged, a fin attached to the flat tube, and a flange that can fix the flat tube. It is a vessel.

The flat tube can be directly joined to the flange by electron beam welding.

The working gas passage may have a circular cross section.

In the heat exchanger for a Stirling refrigerator according to the present invention, a wide flat tube is used as a tube through which the working gas flows, so that the contact area (heat transfer area) with the heat exchange fluid such as air is reduced by the conventional shell. As compared with the AND tube type heat exchanger, the size of the heat exchanger can be increased, and the refrigeration efficiency can be increased.

In a Stirling refrigerator, a working gas such as helium gas reciprocates in a heat exchanger (a radiator or a heat absorber) for the Stirling refrigerator via a regenerator instead of one-way, thereby generating refrigeration. Therefore, in order to minimize the pressure loss, it is not possible to make the tube too long, but there is a conflicting demand that a capacity for moving the working gas in a certain stroke is necessary, but as in the present invention, By adopting a wide flat tube, it is possible to increase the heat transfer area,
A predetermined refrigeration efficiency can be ensured while minimizing pressure loss.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a heat exchanger 20 for a Stirling refrigerator according to an embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIGS. 3 and 4 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a cross-sectional view of a heat exchanger 20 for a Stirling refrigerator. The heat exchanger 20 for a Stirling refrigerator includes a pair of upper and lower flanges 21, a plurality of flat tubes 22,
And fins 23.

The flange 21 includes a gas pipe side flange 24 made of stainless steel and a tube side flange 25 made of aluminum, and a tank portion 26 for temporarily storing a working gas is formed therebetween. . A working gas inlet / outlet portion 27 is formed on each gas pipe side flange 24. The heat exchange fluid such as conditioned air flows in a direction perpendicular to the plane of the paper.

FIG. 2 is a cross-sectional view of the flat tube 22. In the flat tube 22, the aluminum tube main body 28 is formed in a wide band shape in cross section to increase the contact area with the conditioned air. A plurality of working gas channels 29 having a circular cross section are formed. The working gas flow path 29 has a circular cross-sectional shape, and its inner wall surface is formed in a fine wavy shape on the basis of a circular shape, so that the flat tube 22 as a whole has good pressure resistance and helium gas or the like. A large contact area with the working gas can be obtained.

The flat tube 22 is fixed to the flange 21 (tube side flange 25) by directly joining both ends thereof by electron beam welding. That is, since the joining strength is insufficient with the conventional brazing or torch welding, the electron beam welding in which the flat tube 22 is welded to the base material (tube side flange 25) itself of the same material is adopted, and the Pressure resistance is improved by welding.

The fins 23 are attached to the flat tube 22 to further increase the contact area with the heat exchange fluid.

By adopting the heat exchanger 20 for a Stirling refrigerator having such a configuration, the flat tube 22
Surface area of the working gas and the heat-exchanged fluid can be made necessary and sufficient on both the working gas side and the heat-exchanged fluid side. Efficiency can be improved.

If the number of the flat tubes 22 is increased in order to further increase the heat conversion efficiency, there are problems such as leakage of working gas, pressure resistance, and an increase in welding locations. However, the flat tubes 22 themselves are shortened and flattened. In addition, the working gas flow path 29 is made circular in cross section to improve the pressure resistance, and the flat tube 22 and the tube side flange 25 are joined by electron beam welding, so that high strength welding is possible, and Since welding is performed by electronic control, high-precision welding can be realized.

[0028]

As described above, according to the present invention, a fin and flat tube type heat exchanger is used instead of the conventional shell and tube type, so that the refrigeration efficiency and pressure resistance are improved and the air conditioner can be used. It can be suitable.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heat exchanger 20 for a Stirling refrigerator according to an embodiment of the present invention.

FIG. 2 is a sectional view of the same flat tube 22.

FIG. 3 is a structural conceptual diagram of a general Stirling refrigerator 1;

FIG. 4 is a partially cutaway perspective view of a conventional heat exchanger 8 (radiator 8, heat absorber 9) for a Stirling refrigerator of a shell and tube type.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stirling refrigerator (Fig. 3) 2 High-temperature compression chamber 3 Compression cylinder 4 Compression piston 5 Low-temperature expansion chamber 6 Expansion cylinder 7 Expansion piston 8 Radiator (High-temperature side heat exchanger, heat exchanger for Stirling refrigerator) 9 Endotherm Heat exchanger (low-temperature heat exchanger, heat exchanger for Stirling refrigerator) 10 Regenerator (heat accumulator) 11 Crankshaft (drive mechanism) 12 Working gas pipe 13 Cylindrical shell (FIG. 4) 14 Upper and lower pair of flanges 15 Tube Reference Signs List 16 water inlet 17 water outlet 20 heat exchanger for Stirling refrigerator (embodiment, FIG. 1) 21 pair of upper and lower flanges 22 flat tube 23 fin 24 flange stainless steel gas pipe side flange 21 flange 25 aluminum of flange 21 Tube side flange made of steel 26 Tank part 27 Working gas inlet / outlet 28 Flat tube 2 of the tube body 29 having a circular cross section working gas channel

Claims (3)

[Claims] 1. A Stirling refrigerator according to a Stirling cycle that performs a refrigerating action by reciprocating working gas, wherein the heat exchanger for the Stirling refrigerator performs heat exchange between the working gas and a fluid to be heat-exchanged. A wide flat tube having a working gas flow path through which the working gas flows and capable of contacting the heat exchange fluid; a fin attached to the flat tube; and a flange capable of fixing the flat tube. A heat exchanger for a Stirling refrigerator. 2. The heat exchanger for a Stirling refrigerator according to claim 1, wherein the flat tube is directly joined to the flange by electron beam welding. 3. The heat exchanger for a Stirling refrigerator according to claim 1, wherein the working gas passage has a circular cross section.