CN101788207A - Microchannel enhanced heat exchange system of rotary room-temperature magnetic refrigerator and heat transfer method thereof - Google Patents

Abstract

The invention discloses a microchannel enhanced heat exchange system and a heat transfer method of a rotary room temperature magnetic refrigerator, which consists of a working medium plate, a cold end heat exchanger connected thereto, a hot end heat exchanger and a solution pump. The working fluid plate includes a working fluid bed, an inner ring liquid collection tank, an outer ring liquid collection tank, four pairs of interval insulation partitions and multiple inner insulation partitions. The working fluid bed includes multiple trapezoidal microchannel flat tubes, upper magnetic The mass plate and the lower magnetic working medium plate, the trapezoidal microchannel flat tube, the upper magnetic working medium plate and the lower magnetic working medium plate are located between the inner ring liquid sump and the outer ring liquid sump, and the trapezoidal microchannel flat tube is placed between the upper and lower Between two magnetic working plates. The heat transfer method is to make the heat transfer fluid go through a cycle of adiabatic excitation and demagnetization process after passing through different zones of the above-mentioned microchannel enhanced heat exchange system, so that the reciprocating cycle realizes refrigeration. The invention utilizes the characteristic that the microchannel can effectively strengthen the heat exchange due to its scale effect, and applies it to the working medium bed to improve the efficiency of the refrigeration system and reduce the corrosion of the heat exchange fluid to the magnetic working medium.

Description

Microchannel Enhanced Heat Exchange System and Heat Transfer Method of Rotary Room Temperature Magnetic Refrigerator

technical field

The invention relates to the technical field of room temperature magnetic refrigeration and microchannel heat exchange, in particular to a microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator.

Background technique

The emergence of magnetic refrigeration began with the discovery of the magnetocaloric effect 120 years ago, and it began to be applied to low-temperature refrigeration in the 1930s. Since 1975, researchers from all over the world have been conducting experimental research on room temperature magnetic refrigeration. In 1976, G.V.Brown of NASA applied magnetic refrigeration technology to the room temperature range for the first time, using metal gadolinium as the magnetic refrigerant, and obtained a temperature difference of 47K under a 7T magnetic field and no heat load. In December 1996, Carl Zimm, an engineer of American Aerospace Corporation, adopted active cold storage (AMR) technology to build a magnetic refrigerator, which obtained a cooling capacity of 500-600W under a magnetic field of 5T, and achieved a breakthrough in the field of room temperature magnetic refrigeration prototypes. breakthrough progress. At present, the effective heat exchange problem in the room temperature magnetic refrigeration cycle has become one of the key technologies restricting magnetic refrigeration.

Magnetic refrigeration material is a solid substance. In order to complete the refrigeration cycle process, there must be a liquid medium (or gas medium) for heat exchange with the magnetic refrigeration material, which is a solid-liquid or solid-gas heat exchange method. Technically, it is much more complicated than liquid-liquid or liquid-gas heat exchange, and the heat exchange efficiency is lower than them. The heat transfer of the magnetic working medium bed of the existing rotary and reciprocating prototype machines, whether it is a powdery working medium or a layered working medium, usually directly allows the heat exchange fluid (such as water, ethylene glycol solution, etc.) to flow through, There are defects such as large heat exchange resistance of solid working medium and heat exchange fluid, slow heat exchange speed during heat exchange, long refrigeration cycle, low cycle heat exchange efficiency, and corrosion of magnetic working medium. Therefore, how to improve the heat transfer efficiency of the magnetic working medium and the heat exchange fluid is the key to improving the efficiency of magnetic refrigeration.

Since the 1980s, microchannel heat transfer technology has been continuously developed. Microchannel heat exchange is used in other refrigeration systems such as ordinary vapor compression refrigeration systems to improve the efficiency of refrigeration systems, because microchannel heat exchange is effective, microchannel heat exchangers are used to replace ordinary heat exchangers in automotive air conditioners and household air conditioners has become a trend. The microchannel heat exchanger has the following characteristics: (1) Simple structure. Microchannel heat exchangers mainly adopt simple channel structures such as rectangles, triangles, and circular fins; (2) small volume and low flow rate, which can directly act on the heat source position at the millimeter or even micron level; (3) microchannel heat exchangers Due to the size effect of the channel, the thermal resistance is very low, and at the same time, it can directly act on the position of the heat source, so the heat exchange efficiency is high; (4) The operation is stable and reliable. Moreover, there are relatively mature micro-channel processing technologies at present, so it is completely possible to use micro-channel heat exchangers in the working medium bed of rotary magnetic refrigerators to achieve the purpose of enhancing heat transfer and improving its refrigeration efficiency.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the prior art, and to provide a microchannel enhanced heat exchange system for a rotary room temperature magnetic refrigerator, which can reduce the flow resistance of the heat exchange fluid in the process of exchanging heat with the magnetic working medium, thereby improving The efficiency of the rotary room temperature magnetic refrigerator, the compact magnetic working medium heat exchange system, can reduce the use of heat exchange fluid.

The object of the invention is achieved through the following technical solutions:

A micro-channel enhanced heat exchange system for a rotary room temperature magnetic refrigerator, including a working medium plate and a cold end heat exchanger connected thereto, a hot end heat exchanger and a solution pump, and a connection between the cold end heat exchanger and the working medium plate The inlet and outlet of the cold end are connected, while the heat exchanger at the hot end is connected with the inlet and outlet of the heat exchanger at the hot end of the working fluid plate through a solution pump. Insulation partitions and a plurality of thermal insulation partitions in the area, four pairs of interval insulation partitions divide the working medium disk into four parts: the first-level magnetic field area, the transition area, the second-level magnetic field area, and the cold area. It is characterized in that: the The working medium bed consists of multiple trapezoidal microchannel flat tubes, upper magnetic working medium plate and lower magnetic working medium plate, trapezoidal microchannel flat tubes, upper magnetic working medium plate and lower magnetic working medium plate are located in the inner ring liquid sump and outer ring Between the liquid collection tanks, the trapezoidal microchannel flat tube is placed between the upper and lower magnetic working plates.

In the microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator above, the multiple trapezoidal microchannel flat tubes are evenly distributed between the upper and lower magnetic working plates, and the inner ring liquid collection tank and the outer ring collection tank The liquid tanks are connected through trapezoidal microchannel flat tubes.

In the microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator above, the four pairs of interval adiabatic partitions are respectively located between the primary magnetic field area and the transition area, and between the transition area and the secondary magnetic field area, Between the secondary magnetic field area and the cold area, and between the cold area and the primary magnetic field area, it plays a role of heat insulation for each area of the working medium bed; the heat insulation partitions in the multiple areas are located in each area to guide the flow of heat transfer fluid and insulate The effect of heat.

In the microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator above, the upper and lower magnetic working medium plates are circular thin plates, and the trapezoidal microchannel flat tube in the middle layer and the upper and lower magnetic working medium plates pass through The adhesive is formed into one by pressing.

In the microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator described above, the microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator uses water or ethylene glycol solution as the heat transfer fluid.

The heat transfer method of the microchannel enhanced heat exchange system using the above-mentioned rotary room temperature magnetic refrigerator means that when the working medium bed enters the magnetic field, the heat exchange fluid coming out of the cold end heat exchanger passes through the outlet of the cold end heat exchanger Enter the secondary magnetic field area to absorb the heat released by the excitation of the magnetic working fluid, then enter the primary magnetic field area through the entrance of the primary magnetic field area to continue absorbing heat, and then flow into the hot end heat exchanger through the hot end heat exchanger inlet with the solution pump to exchange heat Cooling; when the working fluid bed leaves the magnetic field, the heat exchange fluid cooled from the heat exchanger at the hot end enters the cold zone through the outlet of the heat exchanger at the hot end, and absorbs the cold energy generated by the demagnetization of the magnetic working medium in the cold zone; after cooling , flows into the inlet of the cold end heat exchanger, and absorbs heat from the environment; so far, the magnetic working medium has undergone adiabatic excitation and demagnetization processes, completing a cycle of work, and then repeating the above process to enter the second cycle; rotation The reciprocating cycle of the type magnetic refrigerator realizes refrigeration.

Compared with the prior art, the structure of the microchannel enhanced heat exchange system of the rotary room temperature magnetic refrigerator of the present invention is simple, and the heat exchange area of the working medium disk is effectively and rationally utilized to make the heat exchange fluid flow evenly and reduce the impact of the heat exchange fluid on the magnetic field. Corrosion of the working fluid ensures the safe and effective operation of the rotary refrigerator, and improves the efficiency and cooling capacity of the rotary room temperature magnetic refrigeration system. The effective volume of the magnetic working medium disk of the rotary room-temperature magnetic refrigeration of the present invention is rationally utilized, the resistance during heat exchange between the heat exchange fluid and the magnetic working medium is reduced, the heat exchange effect is more obvious, and the magnetic working medium and the heat exchange fluid are improved. Use efficiency. The microchannel enhanced heat exchange system of the rotary room temperature magnetic refrigerator of the present invention has simple processing technology, good reliability and high stability, and can effectively improve the competitiveness of room temperature magnetic refrigeration. The microchannel enhanced heat exchange system of the rotary room temperature magnetic refrigerator of the present invention solves the problems that the heat exchange efficiency is affected due to the increase of flow resistance when the heat exchange fluid flows through the surface of the working medium plate, and the efficiency of the magnetic refrigeration system is reduced.

Description of drawings

Fig. 1 is the top view of the arrangement mode of the trapezoidal microchannel flat tube of the working medium disk;

2 is a schematic diagram of the principle of a rotary room temperature magnetic refrigerator;

Fig. 3 is a partial sectional view of the working medium bed;

Fig. 4 is a partial structural view of the enlarged working medium bed in Fig. 3 .

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and implementation examples, but the embodiments of the present invention are not limited thereto.

As shown in Figure 1 and Figure 3, the microchannel enhanced heat exchange system of the rotary room temperature magnetic refrigerator includes a layer of trapezoidal microchannel flat tube 1 and two layers of magnetic medium plates 2 (2 in Figure 1 is the lower magnetic work plate working medium plate), inner ring liquid collection tank 3, outer ring liquid collection tank 4, four pairs of interval insulation partitions 5, multiple blocks of internal insulation partitions 6, etc., and the cold end heat exchange connected to it It consists of a heat exchanger, a hot end heat exchanger and a solution pump. The upper magnetic working medium plate 201 and the lower magnetic working medium plate 2 are processed into circular thin plates, and the trapezoidal microchannel flat tube 1 in the middle layer is processed by oxidation and etching on the surface of the silicon substrate 13 by using the existing surface micromachining technology, and then adopts The binder 14 processes the three layers into a working medium bed by means of pressure (as shown in FIG. 4 , which is an enlarged partial structure diagram of the working medium bed). Considering the requirement of cooling capacity, the working medium bed can be formed by alternately stacking multilayer magnetic working medium plates and trapezoidal microchannel flat tubes.

As an embodiment, as shown in Figure 2, the working medium bed is divided into four parts according to the position of the magnetic field, namely the primary magnetic field area (in the range shown in 70 ° on the right side in Figure 2), the transition zone (in the range shown in 80 ° among the figure) Inside), the secondary magnetic field area (in the range of 70° on the left in the figure), and the cold area (in the range of 140° in the figure). The working principle of the microchannel enhanced heat exchange system of the room temperature magnetic refrigerator is: when the working medium bed enters the magnetic field, the heat exchange fluid from the cold end heat exchanger enters the secondary magnetic field area through the outlet 8 of the cold end heat exchanger, absorbing The heat released by the excitation of the magnetic working medium then enters the first-level magnetic field area through the entrance 10 of the first-level magnetic field area to continue absorbing heat, and then flows into the hot-end heat exchanger through the hot-end heat exchanger inlet 11 with the solution pump to exchange heat and cool down; the working fluid bed When leaving the magnetic field, the heat exchange fluid cooled from the heat exchanger at the hot end enters the cold zone through the outlet 12 of the heat exchanger at the hot end, and absorbs the cold energy generated by the demagnetization of the magnetic working medium in the cold zone; after cooling, it flows into the cold end The inlet 7 of the heat exchanger absorbs heat from the environment; so far, the magnetic working medium has undergone the process of adiabatic excitation and demagnetization, completing a cycle of work, and then repeating the above process to enter the second cycle; rotary magnetic refrigeration The machine reciprocates in this way to achieve refrigeration.

The microchannel enhanced heat exchange system of the room temperature magnetic refrigerator of the present invention can effectively and rationally utilize the heat exchange area of the working medium disk, and combines the advantages of microchannel heat exchange, because the trapezoidal microchannel flat tube is used, the heat exchange fluid and The resistance of the magnetic working medium in heat exchange is reduced, and the heat exchange effect is more obvious, which improves the use efficiency and heat exchange efficiency of the magnetic working medium and heat exchange fluid, thereby making the system compact and ensuring the safety and effectiveness of the rotary room temperature magnetic refrigeration system operation, improve the efficiency of the refrigeration system. As above, the present invention can be better implemented.

Claims (7)

1. A microchannel enhanced heat exchange system for a rotary room temperature magnetic refrigerator, including a working medium plate and a cold end heat exchanger connected thereto, a hot end heat exchanger and a solution pump, and a cold end heat exchanger and a working medium The inlet and outlet of the cold end of the plate are connected, and the heat exchanger of the hot end is connected with the inlet and outlet of the heat exchanger of the hot end of the working fluid plate through a solution pump. Groove (4), four pairs of interval heat-insulating partitions (5) and a plurality of internal heat-insulating partitions (6), four pairs of interval heat-insulating partitions (5) divide the working medium disk into a primary magnetic field area and a transition area . The secondary magnetic field area and the cold area are characterized in that: the working medium bed includes a plurality of trapezoidal microchannel flat tubes (1), an upper magnetic working medium plate and a lower magnetic working medium plate, and trapezoidal microchannel flat tubes (1) , The upper magnetic working medium plate and the lower magnetic working medium plate are located between the inner ring liquid collection tank (3) and the outer ring liquid collection tank (4), and the trapezoidal microchannel flat tube (1) is placed on the upper and lower magnetic working medium plates between. 2. The microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator according to claim 1, characterized in that: the plurality of trapezoidal microchannel flat tubes (1) are evenly distributed between the upper and lower magnetic working medium Between the plates, the inner ring liquid sump (3) and the outer ring liquid sump (4) communicate through the trapezoidal microchannel flat tube (1). 3. The microchannel enhanced heat exchange system of a rotary room-temperature magnetic refrigerator according to claim 1, characterized in that: the four pairs of interval adiabatic partitions (5) are respectively located in the primary magnetic field area and the transition area between the transition zone and the secondary magnetic field zone, between the secondary magnetic field zone and the cold zone, and between the cold zone and the primary magnetic field zone, it plays a thermal insulation role for each zone of the working medium bed; the heat insulation in the multiple zones Partition plates (6) are located in each zone to guide the flow of heat transfer fluid and to insulate heat. 4. The microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator according to claim 1, characterized in that: the upper and lower layers of the magnetic working medium plate are circular thin plates, and the trapezoidal microchannel in the middle layer is flat The tube (1) and the upper and lower layers of magnetic working medium plates are formed into one body by means of pressure through an adhesive. 5. The microchannel enhanced heat exchange system of a rotary room temperature magnetic refrigerator according to claim 1, characterized in that water or ethylene glycol solution is used as the heat transfer fluid. 6. A microchannel enhanced heat exchange system for a rotary room temperature magnetic refrigerator according to any one of claims 1 to 5, wherein the working medium bed is composed of multilayer magnetic working medium thin plates and trapezoidal microchannels The flat tubes are stacked alternately. 7. Adopt the heat transfer method of the microchannel enhanced heat exchange system of a kind of rotary room temperature magnetic refrigerator according to any one of claims 1 to 6, characterized in that: when the working medium bed enters the magnetic field, from the cold The heat exchange fluid from the end heat exchanger enters the secondary magnetic field area through the outlet (8) of the cold end heat exchanger, absorbs the heat released by the excitation of the magnetic working medium, and then enters the primary magnetic field area through the entrance (10) of the primary magnetic field area to continue absorb heat, and then flow into the hot end heat exchanger with the solution pump through the hot end heat exchanger inlet (11) to exchange heat and cool down; when the working medium bed leaves the magnetic field, the heat exchange fluid after heat exchange and cooling from the hot end heat The outlet of the end heat exchanger (12) enters the cold zone to absorb the cooling capacity generated by the demagnetization of the magnetic working fluid in the cold zone; after cooling, it flows into the inlet (7) of the cold end heat exchanger to absorb heat from the environment; so far, the magnetic working medium After going through the process of adiabatic excitation and demagnetization, the working process of one cycle is completed, and then the above process is repeated to enter the second cycle; the rotary magnetic refrigerator realizes refrigeration in such a reciprocating cycle.

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