WO2013029328A1

WO2013029328A1 - Swinging magnetic refrigerator under room temperature

Info

Publication number: WO2013029328A1
Application number: PCT/CN2011/084871
Authority: WO
Inventors: 曾德长; 柏占; 郑志刚; 钟喜春; 刘仲武; 余红雅; 邱万奇
Original assignee: 华南理工大学
Priority date: 2011-08-30
Filing date: 2011-12-29
Publication date: 2013-03-07
Also published as: CN102305491A; CN102305491B

Abstract

A swinging magnetic refrigerator under room temperature comprises a magnetic field source system of permanent magnets, a magnetic working medium turntable system, a fluid heat exchanging system and a movement control system. The movement control system controls the operation of a turntable box of the magnetic working medium turntable system, and the magnetic working medium (1-8) is brought to come into and out of the magnetic field space. The magnetic working medium (1-8) positioned in the magnetic field space is magnetized and generates heat. The heat generated by the magnetic working medium is transferred to a hot end heat exchanger by a heat transfer fluid flowing to the hot end heat exchanger, and the hot end heat exchanger further transfers the heat to a high temperature space. The magnetic working medium (1-8) out of the magnetic field space is demagnetized and absorbs heat. The heat transfer fluid flows to a cold end heat exchanger. The magnetic working medium (1-8) absorbs heat from a closed low temperature space by the fluid and the cold end heat exchanger, thereby the refrigeration effect under room temperature and the simplification of the structure of the magnetic refrigerator are obtained.

Description

Swing type room temperature magnetic refrigerator

Technical field

The invention relates to a magnetic refrigerator, in particular to a swing type room temperature magnetic refrigerator.

Background technique

At present, room temperature magnetic refrigeration research is actively carried out in the world, mainly focusing on the preparation of magnetic refrigeration materials and the research of magnetic refrigeration prototypes.

(1) Gd and its compounds. At present, the most typical material that can be used as a magnetic refrigeration cycle is the lanthanide rare earth metal yttrium Gd. Gd has a Curie temperature of 293K, is close to room temperature, and has a large magnetocaloric effect.

(2) Perovskites and perovskite-like compounds. In recent years, large changes in magnetic entropy have been simultaneously found in perovskite manganese oxides having a super magnetocaloric effect, thereby causing widespread concern for such materials. The biggest advantage of this series of compounds is that the cost of Gd and GdSiGe is greatly reduced, the chemical properties are stable (without considering the problem of oxidation prevention), the coercive force is small and the electrical resistivity is large. This series of compounds can easily adjust the Curie temperature to the desired range by doping the sample, but at the same time, the magnetic entropy is reduced too much. In addition, the thermal conductivity of the perovskite manganese oxide is too low, which is not conducive to heat transfer. , the practicality is reduced.

(3) Rare earth-transition intermetallic compounds. In addition to the GdSiGe series of compounds mentioned above, other rare earth-transition intermetallic compounds also have large magnetic entropy changes, and the Curie temperature can be conveniently adjusted by ion doping. For example, MnFePAs, MnAsSb, NiMnGa, La(Fe, Si)13, and the like.

At present, there are two main types of room temperature magnetic refrigeration prototypes, reciprocating room temperature magnetic refrigerators and rotary room temperature magnetic refrigerators. The reciprocating type has the disadvantage of low efficiency, while the rotary type has the disadvantages of complicated structure and the working disk is subjected to the unilateral force.

Summary of the invention

In order to solve the disadvantages of low efficiency of the reciprocating room temperature magnetic refrigerator and complicated structure of the rotary room temperature magnetic refrigerator, and the working disk is subjected to the unilateral force, the present invention provides a swing type room temperature magnetic refrigerator. The technical solution is as follows:

An oscillating room temperature magnetic refrigerator, comprising a permanent magnet magnetic field source system, a magnetic working disk turntable system, a fluid heat exchange system, and a motion control system;

Permanent magnet magnetic field source system: symmetrically arranged by two identical permanent magnet systems, including a permanent magnet providing an excitation source and an E-type magnetically permeable frame for magnetic conduction, a magnet in the middle of the magnetically permeable frame The core divides the whole frame into upper and lower sections, and the outer end of the magnetic core is a platform structure protruding upward and downward; two magnetic conductive materials are respectively disposed in the upper and lower sections, and the outer end of the magnetic conductive material and the magnetic core The outer end is flush, the inner end is separated from the inner wall of the frame, and a working gap is formed between the magnetic conductive material and the platform of the magnetic core. In the magnetic conductive frame interval outside the working gap, the filling is filled in the direction determined by the Halbach rotation theorem. a permanent magnet in the magnetic direction;

Magnetic working medium turntable system: including rotating shaft and eight turntable boxes fixed on the rotating shaft, the turntable box is divided into two layers, four on each layer, and symmetrically arranged, wherein the two opposite turntables in the upper layer and the lower layer are symmetrical The two turntable boxes are respectively located in the four working gaps of the two permanent magnet systems; the magnetic working medium is respectively placed in the eight turntable boxes, and the magnetic working medium enters and exits the magnetic field with the rotation of the rotating shaft; the four located in the working gap The magnetic working fluid cartridges are sequentially connected to form a heat generating group through a fluid pipeline, and the other four magnetic working fluid cartridges are sequentially connected by a fluid pipeline to form an endothermic group;

The fluid heat exchange system includes a hot end heat exchanger, a low temperature sealed space, and a cold end heat exchanger enclosed therein; the refrigeration is controlled by a motion control system, wherein the cooling process is: the fluid flows along the pipeline driven by the water pump The four magnetosomes in the endothermic group pass through the cold-end heat exchanger, and the fluid flowing out of the cold-end heat exchanger flows through the four magnetosomes of the exothermic group, and then flows through the hot-end heat exchanger, and the heat The end dissipates heat into the air.

The motion control system comprises: a programmable logic controller (PLC), a stepping motor and a solenoid valve, wherein the electromagnetic valves are divided into two groups, and the control process of the motion control system is: when programmable The controller issues a command to cause a set of magnetic working fluid cartridges to enter the magnetic field region driven by the stepping motor. At this time, the programmable controller issues a command to open a group of solenoid valves and pumps to complete a refrigeration process; then programmable control The stepping motor rotates the rotating shaft 90 degrees to make another set of magnetic working chambers enter the magnetic field; the programmable controller issues a command to switch to another set of solenoid valves to open, complete the second cooling process; then programmable control The stepping motor rotates the rotating shaft in the reverse direction by 90 degrees, repeats the first cooling process, and sequentially performs cooling.

The magnetically permeable material is fixed to the E-shaped magnetically permeable frame.

The protruding platform width accounts for 30% to 50% of the width of the magnetic core.

A gap is left between the inner end surface of the magnetic conductive material and the permanent magnet filled on one side thereof.

The width of the magnetically permeable material is the same as the width of the protruding platform.

The permanent magnet system has a fan shape in cross section.

The permanent magnet is a rare earth neodymium iron boron permanent magnet; the magnetic conductive core frame and the magnetic conductive material are all electrical pure iron.

The principle of the invention is that the rotating shaft oscillates the magnetic working medium into and out of the magnetic field space, and the magnetic working medium in the magnetic field space is magnetized and exothermic, and the heat transfer fluid flows to the hot end heat exchanger, and the heat generated by the magnetic working medium is transferred to the hot end heat. The exchanger, the hot end heat exchanger transfers heat to the high temperature space; the magnetism in the magnetic field space demagnetizes and absorbs heat, the heat transfer fluid flows to the cold end heat exchanger, and the magnetic medium passes through the fluid and the cold end heat exchanger from the low temperature The confined space absorbs heat.

The effects and advantages of the technical solution provided by the present invention are:

(1) Control the movement of the magnetic medium turntable box by the motion control unit, control the flow direction of the heat transfer fluid by controlling the electromagnetic reversing valve, and integrate the two independent fluid cycles into one fluid circulation, thereby completing the magnetic refrigerator The cycle process achieves the cooling effect at room temperature and simplifies the structure of the magnetic refrigerator; it has the advantages of simple structure of the reciprocating room temperature magnetic refrigerator and the high efficiency of the rotary room temperature magnetic refrigerator.

(2) Due to the double air gap permanent magnet structure, the 180 degree symmetric fixed arrangement effectively reduces the magnetic unilateral tension and axial force of the magnetic working disk, and increases the service life of the turntable.

(3) The rotating shaft moves in a manner of swinging about 90 degrees, and the fluid pipe connecting the magnetic working disk turntable box is almost motionless, thereby avoiding the entanglement of the pipe, greatly simplifying the fluid piping system and reducing the cost.

(4) The internal fluid pipeline of the magnetic working disk turntable adopts multi-stage series connection, which further simplifies the pipeline structure and enables progressive cooling.

(5) The permanent magnet system of the present invention has the following advantages: a symmetrical structure having a double air gap, which can simultaneously excite (demagnetize) two parts of the magnetic working medium, thereby making the structure of the room temperature magnetic refrigerator more compact and efficient; The uniformity of the magnetic field strength is good, which reduces the heat exchange between the working fluids during the excitation (demagnetization) process, thereby improving the cooling efficiency; the symmetrical structure with double air gaps can greatly reduce the axial force when properly installed. Reduce the input power and improve the cooling efficiency; have a larger air gap field space, which is beneficial to load more magnetic working medium and improve the cooling capacity of the room temperature magnetic refrigerator.

DRAWINGS

1 is a schematic cross-sectional view of a permanent magnet system of the present invention.

2 is a schematic view showing the structure of a permanent magnet system used in a swing type room temperature magnetic refrigerator.

Fig. 3 is a schematic view showing the arrangement of the excitation source permanent magnets of the swing type room temperature magnetic refrigerator.

Fig. 4 is a schematic view showing the wiring of the fluid line of the working medium turntable box in the swing type room temperature magnetic refrigerator.

Fig. 5 is a schematic view showing the swinging motion of the swing type room temperature magnetic refrigerator.

Figure 6 is a schematic diagram of the principle of a swing type room temperature magnetic refrigerator.

Figure 7 is a magnetic line diagram of the permanent magnet structure.

Figure 8 is a graph showing the distribution of magnetic field strength in the working gap.

detailed description

The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

The embodiment provides an oscillating room temperature magnetic refrigerator, comprising a permanent magnet magnetic field source system, a magnetic working disk turntable system, a fluid heat exchange system, and a motion control system.

Permanent magnet magnetic field source system: symmetrically arranged by two identical permanent magnet systems, the permanent magnet system, the cross-sectional structure is shown in Figure 1, and the three-dimensional structure is shown in Figure 2, including the permanent magnets that provide the excitation source and the magnetic permeability. The action of the E-type magnetic permeable frame 9, the magnetic core 3 in the middle of the magnetic permeable frame 9 divides the entire frame into two upper and lower sections, and the outer end of the magnetic core 3 is a platform structure protruding upward and downward; the protruding platform The width is 40% of the width of the magnetic core. Two layers of magnetically

permeable materials

1, 5 are respectively disposed in the upper and lower sections, and the magnetic

permeable materials

1, 5 are fixed to the E-shaped magnetic permeable frame 9. The outer ends of the magnetic

conductive materials

1, 5 are flush with the outer ends of the magnetic core 3, the inner ends are separated from the inner walls of the frame 9, and the magnetic

conductive materials

1, 5 are formed between the upper and

lower protruding platforms

4, 2 of the magnetic core. In the working gap,

permanent magnets

6, 7, 8, 10, 11, 12 in different magnetization directions are filled in the direction determined by the Halbach rotation theorem between the magnetically

permeable materials

1, 5 and the frame 9 outside the working gap. A gap is left between the inner end surface of the magnetic

conductive material

1, 5 and the filled

permanent magnets

8, 10, and the width of the magnetic conductive material is the same as the width of the upper and

lower protruding platforms

4, 2, thereby increasing the size and uniformity of the magnetic field. degree. The permanent magnet is a rare earth neodymium iron boron permanent magnet; the magnetic conductive core frame and the magnetic conductive material are all electrical pure iron. The upper curve of Figure 8 represents the magnetic field strength distribution of the upper working gap, and the lower curve represents the magnetic field strength distribution of the working gap below. It can be seen that the fan-shaped permanent magnet used in the rotary magnetic refrigerator has a very large working gap, and this space is completely filled with the magnetic refrigerant metal Gd, and its quality reaches 3100. g. By reducing the size of the working gap or increasing the relative size of the magnet, the magnetic field strength of the working gap will be further increased. In the magnetic refrigerator, two sets of magnet systems and two sets of magnetic working materials are used. For this structure, the axial magnetic pulling force and the radial magnetic pulling force produced by the whole system are substantially zero.

As shown in FIG. 3, two identical permanent magnet systems shown in FIG. 1 are symmetrically arranged 180 degrees, so that the arrangement can better utilize the advantages of the double air gap magnetic field and reduce the axial force and magnetic force of the magnetic working disk turntable box. Unilateral force. A magneto-optical turntable is mounted in a plane of the two-layer magnetic field air gap, and the rotating shaft is located on the central axis for driving the magnetic medium into and out of the magnetic field.

Magnetic working medium turntable system: including rotating shaft and eight turntable boxes fixed on the rotating shaft. According to the characteristics of the excitation source, the magnetic working medium turntable box is designed as a double-layer structure, and each layer is divided into four, and symmetrically arranged, the turntable The magnetic medium (metal Gd) is loaded in the box, wherein two rotisserie boxes in the upper layer and two rotisserie boxes in the lower layer are respectively located in four working gaps of the two permanent magnet systems; the magnetic working medium For the magnetic refrigeration material, the magnetic working medium enters and exits the magnetic field with the rotation of the rotating shaft; thus, when the refrigerator is running, half of the magnetic working medium is in the exciting heat release, and half is in the demagnetizing endothermic state, which is improved compared with the conventional rotating type. Cooling efficiency.

In order to clearly explain the wiring condition of the fluid pipeline of the magnetic working disk turntable, as shown in Fig. 4, the upper and lower boxes are placed in the same plane, and the dotted line is the position of the magnet, which can easily represent the magnetic field. 2, 3, 4, 5, 6, 7, 8 are small boxes loaded with magnetic working fluid. The

magnetisms

1, 3, 5, and 7 in Fig. 4 are excited in a magnetic field to conduct heat, and the solid line indicates a heat exchange fluid pipe in which 1, 3, 7, and 5 are sequentially connected, and finally heat exchange is performed to the hot end. . The remaining

magnetosomes

2, 4, 6, and 8 are also connected in a similar manner, as indicated by dotted lines. The method of step-by-step series connection is used to connect the magneto-plastic capsules of the upper and lower layers in the excitation (demagnetization) state by pipes, which greatly simplifies the arrangement of the fluid pipelines and can realize the hierarchical cooling.

The room temperature magnetic refrigerator provided by the present invention is called a swing type, and its biggest feature is that its motion mode is neither a conventional reciprocating linear type nor a conventional rotating type, but a swing type similar to a pendulum. During operation, the rotating shaft is first rotated 90 degrees counterclockwise, the rotating shaft is temporarily 4S, the fluid is passed, and then rotated 90 degrees clockwise. The rotating shaft is again suspended for 4S, and the fluid is circulated. The characteristic of the oscillating type is that there is no problem of entanglement and entanglement of the pipeline, and it is not necessary to equip the complicated fluid distribution valve, so the fluid pipeline can be as simple as reciprocating; at the same time, the angular positioning can realize the rapid positioning of the magnetic plastid cartridge. To increase the operating frequency of the refrigerator.

The fluid heat exchange system includes a hot end heat exchanger, a low temperature sealed space, and a cold end heat exchanger sealed therein; the refrigeration is controlled by a motion control system: the programmable controller, the stepping Motor and solenoid valve, the solenoid valve is a total of 4, divided into two groups. The refrigeration process is further described below with reference to the accompanying drawings:

As shown in Figure 5, the upper part of the magnetic working disk carousel, in the initial state, 1, 3 excitation heat release, 2, 4 demagnetization endothermic, counterclockwise rotation of 90 degrees, 1, 3 demagnetization, 2, 4 The excitation is exothermic, the rotating shaft is suspended, the fluid is transferred to heat, and then rotated 90 degrees clockwise to return to the starting position, and the above steps are cycled to achieve cooling.

As shown in Figure 6, starting from the beginning of the diagram:

1 The magnetic

medium capsules

1, 3, 5, and 7 are in an excited state, and the magnetic

medium capsules

2, 4, 6, and 8 are in a demagnetized state.

2 Open the water pump, solenoid valves K2 and K3 through the programmable controller, close the solenoid valves K1, K4, and the fluid will flow through the 2, 4, 6, and 8 under the drive of the pump (the direction of the arrow is the direction of fluid movement). To the cold end, the fluid flowing out of the cold end flows through 1, 3, 5, 7 to bring the heat released to the hot end, the hot end dissipates the heat to the air, and the fluid flows out of the hot end to complete a cycle. The pump is turned off when the fluid transfers the heat generated by the magnetic medium.

3 Programmable controller controls the stepping motor to drive the rotating shaft to rotate counterclockwise by 90 degrees, the magnetoplasmic

small boxes

1, 3, 5, 7 are in the demagnetization state, and the magnetic

medium capsules

2, 4, 6, and 8 are in the excited state. .

4 Programmable controller controls to open the water pump, solenoid valves K1 and K4, close the solenoid valves K2 and K3, the fluid flows through the pumps, 1, 3, 5, 7 to transfer the low temperature to the cold end heat exchanger, out of the cold end The heat exchanger fluid flows through 2, 4, 6, and 8 to bring the heat it releases to the hot end heat exchanger. The hot end dissipates heat to the air, and the fluid flows out of the hot end to complete a cycle. The pump is turned off when the fluid transfers the heat generated by the magnetic medium.

5 The motion control system controls the stepping motor to drive the rotating shaft to rotate 90 degrees clockwise, and returns to step 1. Cycle through the above steps to achieve the cooling effect.

Claims

An oscillating room temperature magnetic refrigerator characterized by comprising a permanent magnet magnetic field source system, a magnetic working fluid turntable system, a fluid heat exchange system, and a motion control system;

Permanent magnet magnetic field source system: symmetrically arranged by two identical permanent magnet systems, including a permanent magnet providing an excitation source and an E-type magnetically permeable frame for magnetic conduction, a magnet in the middle of the magnetically permeable frame The core divides the whole frame into upper and lower sections, and the outer end of the magnetic core is a platform structure protruding upward and downward; two magnetic conductive materials are respectively disposed in the upper and lower sections, and the outer end of the magnetic conductive material and the magnetic core The outer end is flush, the inner end is separated from the inner wall of the frame, and a working gap is formed between the magnetic conductive material and the platform of the magnetic core. In the magnetic conductive frame interval outside the working gap, the filling is filled in the direction determined by the Halbach rotation theorem. a permanent magnet in the magnetic direction;

Magnetic working medium turntable system: including rotating shaft and eight turntable boxes fixed on the rotating shaft, the turntable box is divided into two layers, four on each layer, and symmetrically arranged, wherein the two opposite turntables in the upper layer and the lower layer are symmetrical The two turntable boxes are respectively located in the four working gaps of the two permanent magnet systems; the magnetic working medium is respectively placed in the eight turntable boxes, and the magnetic working medium enters and exits the magnetic field with the rotation of the rotating shaft; the four located in the working gap The magnetic working fluid cartridges are sequentially connected to form a heat generating group through a fluid pipeline, and the other four magnetic working fluid cartridges are sequentially connected by a fluid pipeline to form an endothermic group;

The fluid heat exchange system includes a hot end heat exchanger, a low temperature sealed space, and a cold end heat exchanger enclosed therein; the refrigeration is controlled by a motion control system, wherein the cooling process is: the fluid flows along the pipeline driven by the water pump The four magnetic working substances in the heat absorption group pass through the cold end heat exchanger, and the fluid flowing out of the cold end heat exchanger flows through the four magnetic working materials of the heat release group and then flows through the hot end heat exchanger.
The magnetic refrigerator according to claim 1, wherein the motion control system comprises: a programmable controller, a stepping motor and a solenoid valve, wherein the electromagnetic valves are divided into two groups, and are divided into two groups; The control process of the motion control system is: when the programmable controller issues a command to cause a group of magnetic working fluid cartridges to enter the magnetic field region driven by the stepping motor, the programmable controller issues commands to make a group of solenoid valves and pumps Open, complete a cooling process; then the programmable controller controls the stepping motor rotation axis to rotate 90 degrees, so that another set of magnetic working boxes enters the magnetic field; the programmable controller issues a command to switch to another set of solenoid valves to open, The second refrigeration process is completed; then the programmable controller controls the rotation axis of the stepping motor to reverse 90 degrees, repeats the first refrigeration process, and sequentially performs cooling.
A magnetic refrigerator according to claim 1 or 2, wherein said magnetically permeable material is fixed to the E-shaped magnetically permeable frame.
The magnetic refrigerator according to claim 3, wherein said protruding platform width accounts for 30% to 50% of the width of the magnetic core.
The magnetic refrigerator according to claim 4, wherein a gap is left between the inner end surface of the magnetic conductive material and the permanent magnet filled on one side thereof.
The magnetic refrigerator according to claim 5, wherein the width of the magnetically permeable material is the same as the width of the protruding platform.
A magnetic refrigerator according to claim 6, wherein said permanent magnet system has a fan shape in cross section.
The magnetic refrigerator according to claim 7, wherein the permanent magnet is a rare earth neodymium iron boron permanent magnet; and the magnetic conductive core frame and the magnetic conductive material are all electrical pure iron.