JP2000121189A - Split stirling refrigerator and method for designing split stirling refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a large COP value and to easily design and manufacture a refrigerator by calculating an intrinsic frequency from a weight of a heat exchanger and a spring constant of a machine spring amount at the exchanger, and setting a ratio of the frequency to a driving frequency to a value of a specific range. SOLUTION: The split Stirling refrigerator comprises a compressor 11, a cold head (expansion unit) 12, and a capillary tube 13 for connecting them. A natural frequency is calculated from weight of a displacer cool storage unit 32 (heat exchanger) of the head and a spring constant of a displacer control spring 33 (machine spring) mounted at the unit 32, and the refrigerator is designed and manufactured so that a ratio of the frequency to a driving frequency (normally 50 or 60 Hz) of the compressor 11 falls within a range of 0.97 to 1.3. Thus, the refrigerator can obtained a large COP (refrigerating capability/ consumption power) value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a split type Stirling refrigerator which is a refrigerator using a Stirling cycle in which a compressor and a cold head are connected by a capillary tube, and a design method thereof.

[0002]

2. Description of the Related Art As one type of refrigerator, a refrigerator called a Stirling refrigerator using a Stirling cycle (also called a reverse Stirling cycle or a Kirk cycle) is known. Stirling refrigerators are broadly divided into those in which a compressor and a cold head are connected by a crank mechanism and those in which they are not connected. (Referred to as a split-type Stirling refrigerator).

[0003]

A split type Stirling refrigerator has a large COP (Coefficient Of Perfor
mance (refrigeration capacity / power consumption) value is desired. However, conventionally, the design and manufacture of the split type Stirling refrigerator have been performed by a trial-and-error procedure, and the COP value has been at most about 2.3%.

Accordingly, an object of the present invention is to provide a larger CO
An object of the present invention is to provide a split type Stirling refrigerator having a P value.

Another object of the present invention is to provide a larger C
An object of the present invention is to provide a design method of a split type Stirling refrigerator which can design a split type Stirling refrigerator having an OP value.

[0006]

As a result of diligent studies to solve the above problems, the present inventors have found that the weight of the heat exchanger provided in the cold head and the mechanical spring attached to the heat exchanger If the ratio of the natural frequency calculated from the constant to the drive frequency is set to a value in the range of 0.97 to 1.3, particularly about 1.1, a split type Stirling refrigerator having a large COP value Was obtained.

In the design of the split type Stirling refrigerator which satisfies the above conditions, the driving frequency is determined in advance, and the "natural frequency / driving frequency" is 0.97 to
The natural frequency may be determined so as to have a value within the range of 1.3, or the natural frequency may be determined in advance, and then the driving frequency may be determined. Can be. Further, in order to set the natural frequency of the heat exchanger to a desired value, the weight of the heat exchanger may be changed or the spring constant of the mechanical spring may be changed. However, the adjustment of the driving frequency and the adjustment of the weight are often complicated operations, so that it is desirable to adjust the spring constant of the mechanical spring so that the above condition is satisfied.

[0008]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, the configuration and operation of a split-type Stirling refrigerator according to an embodiment of the present invention will be described with reference to FIG.

As shown in the figure, the split type Stirling refrigerator of the embodiment comprises a compressor 11 and a cold head 1.
2 and a capillary tube 13 connecting them.

The compressor 11 includes a yoke 21 and a pressure-holding vessel 22.
And a compression piston 23 and a piston control spring 24. As shown, the yoke 21 has a structure that functions as a cylinder of the compression piston 23, and the movable coil 2 fixed to the compression piston 23.
5 is provided with an annular groove into which is inserted, and a permanent magnet 26 embedded so as to form an outer inner wall of the groove.

The pressure holding container 22 is fixed to the yoke 21 and forms a pressure holding space in which the compression piston 23 is accommodated and which is filled with an inert gas such as helium. . Although not shown, an airtight power supply terminal is provided in the pressure holding container 22, and the movable coil 25 is connected to an external power supply via the confidential power supply terminal. The piston control spring 24 is provided between the compression piston 23 and the pressure holding container 22 so as to connect the compression piston 23 and the pressure holding container 22 (to maintain the compression piston 23 at a neutral point).

The cold head 12 has a housing 31 whose inner space functions as a cylinder, a displacer regenerator 32 which is a displacer containing a regenerator material (such as a wire mesh) for heat exchange, and a displacer regenerator 32 which is neutralized. A displacer control spring 33 is provided for keeping the point.

The split type Stirling refrigerator controls the compression piston 23 to reciprocate (moving in the left-right direction in the figure) by supplying an alternating current to the movable coil 25 via a hermetic power supply terminal. Is done. As a result, in the system space consisting of the compression space 28, the expansion space 34, and the ineffective space, a cycle consisting of four strokes of isothermal compression, equal volume transfer, isothermal expansion, and equal volume transfer is repeated and attached to the cold head 12. For example, the cooling of the thermal load such as the infrared detecting element is performed.

In short, the basic structure and operation of the split-type Stirling refrigerator according to the embodiment are the same as those of the conventional split-type Stirling refrigerator equipped with a compressor using a linear motor. However, the split type Stirling refrigerator of the embodiment has a natural frequency calculated from the weight of the displacer regenerator 32 (heat exchanger) provided in the cold head and the spring constant of the displacer control spring 33 (mechanical spring) attached thereto. Of the compressor 11 (usually 5
(0 or 60 Hz) is designed and manufactured so as to fall within a range of 0.97 to 1.3.

A split-type Stirling refrigerator manufactured based on a design that imposes such conditions exhibits a larger COP value than before. In the following,
FIG. 2 is a diagram showing the COP measurement results of several split-type Stirling refrigerators using mechanical springs having different spring constants as the displacer control spring 33 (changing the cold head mechanical frequency). This will be specifically described.

As shown in the drawing, the COP value of the split type Stirling refrigerator is calculated when the ratio of the cold head mechanical frequency to the driving frequency is about 1.1 or less.
It increases with an increase in the ratio, and decreases with an increase in the cross-sectional area ratio when the cross-sectional area ratio is about 1.1 or more. As described above, the COP value of the conventional split-type Stirling refrigerator is at most 2.3% (indicated by a dotted line in the figure). It can be seen that if the value is designed to fall within the range of 1.3, a split Stirling refrigerator having a larger COP value than the conventional split Stirling refrigerator can be obtained. In addition, it can be seen that a split type Stirling refrigerator having an extremely large COP value can be obtained particularly when the frequency ratio is set to about 1.1.

Although the split-type Stirling refrigerator described as the embodiment uses a linear motor, the above technology can be applied to a split-type Stirling refrigerator using a rotary motor.

[0018]

As described above, the split type Stirling refrigerator according to the present invention has a large COP value. Therefore, according to the present invention, the split type Stirling refrigerator has a smaller power consumption or a higher cooling capacity. A Stirling refrigerator will be obtained. Further, according to the method of designing a split-type Stirling refrigerator according to the present invention, such a split-type Stirling refrigerator can be easily designed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a split-type Stirling refrigerator according to an embodiment of the present invention.

FIG. 2 shows the CO of a split type Stirling refrigerator having different ratios of the mechanical frequency of the cold head to the driving frequency.
It is the graph which showed the measurement result of P value.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Compressor 12 Cold head 13 Capillary tube 21 Yoke 22 Pressure holding container 23 Compression piston 24 Piston control spring 25 Moving coil 26 Permanent magnet 28 Compression space 31 Housing part 32 Displacer regenerator (heat exchanger) 33 Displacer control spring (mechanical spring) ) 34 Expansion space

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Uchida 2-1-1 Tanidocho, Tanashi-shi, Tokyo Sumitomo Heavy Industries, Ltd. Inside Tanashi Factory (72) Inventor Yoshito Taguchi 2-chome, Yatocho, Tanashi-shi, Tokyo No. 1-1 Sumitomo Heavy Industries, Ltd. Tanashi Factory

Claims (3)

[Claims] 1. A split type Stirling refrigerator in which a compressor and a cold head are connected by a capillary tube, wherein a weight of a heat exchanger provided in the cold head and a spring constant of a mechanical spring attached to the heat exchanger are determined. The ratio of the calculated natural frequency to the drive frequency of the compressor is a value within a range of 0.97 to 1.3. 2. The split-type Stirling refrigerator according to claim 1, wherein the ratio is approximately 1.1. 3. A design method of a split type Stirling refrigerator in which a compressor and a cold head are connected by a capillary tube, wherein a weight of a heat exchanger provided in the cold head and a spring of a mechanical spring attached to the heat exchanger are provided. The ratio of the natural frequency calculated from the constant to the drive frequency of the compressor is designed to be a value within the range of 0.97 to 1.3. Design method.