WO2018040034A1

WO2018040034A1 - Micro-channel heat exchanger and air-cooled refrigerator

Info

Publication number: WO2018040034A1
Application number: PCT/CN2016/097686
Authority: WO
Inventors: 唐学强; 孟宪春; 任伟
Original assignee: 合肥美的电冰箱有限公司; 合肥华凌股份有限公司; 美的集团股份有限公司
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2018-03-08

Abstract

Provided are a micro-channel heat exchanger (100) and an air-cooled refrigerator. The micro-channel heat exchanger (100) comprises two collecting pipes (1), a plurality of heat exchange pipes (2) and at least one fin (3), the two collecting pipes (1) being arranged parallel to each other. Two ends of the plurality of heat exchange pipes (2) are connected to the two collecting pipes (1) respectively, the plurality of heat exchange pipes (2) bend along the lengthwise direction thereof to form a plurality of pipe layers (20), and the flow area of some of the heat exchange pipes (2) is larger than that of the remaining heat exchange pipes (2). Each fin (3) is arranged between two adjacent pipe layers (20) or on the outside of the outermost pipe layer (20), and each fin (3) extends in a corrugated form in the extension direction of the heat exchange pipes (2). Each fin (3) extends continuously in the extension direction of the collecting pipes (1).

Description

Microchannel heat exchanger and air-cooled refrigerator

Technical field

The invention relates to the field of refrigeration and heat dissipation equipment, in particular to a microchannel heat exchanger and an air-cooled refrigerator.

Background technique

The development of microchannel heat transfer technology engineering originates from the requirement of high-density electronic device cooling and heat transfer of micro-electro-mechanical systems. Due to its compact structure and high heat exchange efficiency, microchannel technology in the domestic market is the first in the automotive air-conditioning industry. Industrialization development.

The refrigeration system using the new generation of natural refrigerant CO2 is a supercritical cycle, and the system pressure is high. For example, in an air conditioning system, the high-pressure working pressure of the system should be above 13 MPa, and the design pressure should reach 42.5 MPa, which puts high demands on the pressure resistance of the compressor and the heat exchanger. Under the premise of compact structure, the microchannel condenser can simultaneously meet the pressure resistance, durability and system safety. With the improvement of production technology, microchannel heat exchangers have gradually become the darling of the heat exchanger industry, and the application industry is more and more. Due to the increasing volume ratio of refrigerators, the use of microchannel evaporators in refrigerators has become one of the development trends of refrigerators.

The common microchannel evaporator has a small fin gap and a small fin length. When applied to the refrigerator, the frost layer accumulates too fast, and the frost layer easily blocks the fin gap, resulting in a short defrosting interval of the refrigerator and defrosting. frequently. At the same time, due to the short fins in the defrosting process, the moisture on the fins is not easy to accumulate into drops, which makes it difficult to drain the defrosting water, and finally forms ice on the surface of the evaporator, which affects the heat exchange effect.

Summary of the invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, one aspect of the present invention is directed to a microchannel heat exchanger that is easy to drain defrosting water during defrosting.

Another object of the present invention is to provide an air-cooled refrigerator having the above-described microchannel heat exchanger.

The microchannel heat exchanger according to the present invention comprises: two headers, the two headers are arranged in parallel; a plurality of heat exchange tubes, the two ends of the plurality of heat exchange tubes are respectively connected to the two a collecting tube, the plurality of heat exchange tubes are bent along a length thereof to form a plurality of tube layers, and a portion of the heat exchange tubes has a flow area larger than a flow area of the remaining heat exchange tubes; at least one fin, Each of the fins is disposed between adjacent two of the tube layers or outside the tube layer disposed at the outermost layer, and each of the fins is corrugated in a direction in which the heat exchange tubes extend Extending, each of the fins extends continuously in the direction in which the header extends.

According to the microchannel heat exchanger of the embodiment of the present invention, each fin is corrugated in the extending direction of the heat exchange tube by providing fins on the outer side of the adjacent tube layer or the outermost tube layer, in the header Each fin in the direction of extension Continued extension, so that during the defrosting process of the microchannel heat exchanger, the frosted water on the surface of the fin can accumulate into water droplets, and the water droplets can smoothly slide down along the continuous fins and drain away, which solves the problem that the surface of the fins is large in water and cannot be discharged. The exhaustion problem can prevent the ice on the surface of the microchannel heat exchanger from affecting the heat exchange efficiency. By setting the flow area of the partial heat exchange tube to be larger than the flow area of the remaining heat exchange tubes, the heat exchange tube can be disposed at the first windward side of the microchannel heat exchanger, thereby promoting the refrigerant of the plurality of heat exchange tubes. The flow rate is uniform, and the overall heat exchange capacity of the heat exchanger is improved.

In some embodiments, the flow areas of the plurality of heat exchange tubes are sequentially increased or decreased sequentially in the extending direction of the header, and each of the two adjacent heat exchange tubes is located on the windward side. The flow area of the heat exchange tube is larger than the flow area of the heat exchange tube located on the leeward side. Therefore, the difference in the flow area of the heat exchange tubes passing through the refrigerant layers of each layer is set, and the difference in pressure drop loss of the heat exchange tubes of each layer is reduced, and finally, the refrigerant is evenly distributed in the plurality of heat exchange tubes, thereby Further improve the overall heat exchange capacity of the heat exchanger.

Specifically, the heat exchange tubes are three, and the ratio of the flow areas of the three heat exchange tubes in the extending direction of the header is 2:3:4.

In some embodiments, at least one of the fins includes a first fin segment and a second fin segment, the first fin segment having a size greater than a dimension of the second fin segment in an extension direction of the header . Thereby, air can be easily blown between the inner tube layers of the microchannel heat exchanger, increasing the distribution space of the frost layer, reducing the amount and speed of frost layer accumulation at the bottom of the fin, and reducing the frosting on the microchannel. The performance of the heater affects the defrosting cycle.

Optionally, in the extending direction of the header, the size of the second fin segment is 0.67-0.75 of the size of the first fin segment.

In some embodiments, the first fin segment and the second fin segment in each of the fins are connected to all of the heat exchange tubes in the tube layer in which they are located. This ensures that all heat exchange tubes can be connected and fixed to the fins.

Specifically, in the extending direction of the header, the contact dimension between the windward side of the second fin segment and the outermost heat exchange tube on the tube layer where the tube segment is located is 5-10 mm . Thereby, it is ensured that the fins are in contact with the outermost heat exchange tubes, and the water droplets on the fins cannot be prevented from flowing down to the outermost heat exchange tubes when the fins are suspended.

According to the air-cooled refrigerator of the present invention, the air-cooled refrigerator defines a refrigerating compartment and a duct, the duct having a return air inlet for entering air from the refrigerating compartment, the air-cooling refrigerator including the above according to the present invention In the microchannel heat exchanger of the embodiment, the microchannel heat exchanger is disposed in the air duct.

According to the air-cooled refrigerator of the embodiment of the invention, the microchannel heat exchanger is arranged to facilitate the exhaustion of the defrosting water on the microchannel heat exchanger during defrosting, preventing the ice on the surface of the microchannel heat exchanger from affecting the heat exchange. effectiveness.

In some embodiments, the microchannel heat exchanger is the above-described microchannel heat exchanger having a first fin segment and a second fin segment, the microchannel heat exchanger being disposed in the air duct, the two The headers are vertically disposed, and the second fin segments of the fins are disposed above the return air vents. Thus, by providing the above microchannel heat exchanger, the distribution space of the frost layer is increased, the amount and speed of the frost layer accumulation at the bottom of the fin are reduced, and the frosting is reduced to the microchannel heat exchanger. Can affect and extend the defrosting cycle.

Specifically, the horizontal width of the second fin segment is substantially 1.1-1.4 times the horizontal width of the corresponding return air opening. In this way, the fins can be avoided as far as possible from the return air outlet, and the return air can be blown to the microchannel heat exchanger.

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from

1 is a perspective view of a microchannel heat exchanger in accordance with an embodiment of the present invention.

2 is a top plan view of a microchannel heat exchanger in accordance with an embodiment of the present invention.

3 is a perspective view of a fin used in a microchannel heat exchanger in accordance with an embodiment of the present invention.

4 is a cross-sectional view of a microchannel heat exchanger in accordance with an embodiment of the present invention.

Figure 5 is a cross-sectional enlarged enlarged view of three heat exchange tubes of a microchannel heat exchanger according to an embodiment of the present invention.

Reference mark:

Microchannel heat exchanger 100,

Collector 1,

Heat exchange tube 2, tube layer 20, tube section 21, straight section 211, curved section 212, first heat exchange tube 201, second heat exchange tube 202, third heat exchange tube 203, flow passage 210,

The fin 3, the first fin segment 31, and the second fin segment 32.

detailed description

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

A microchannel heat exchanger 100 in accordance with an embodiment of the present invention will now be described with reference to Figs.

According to the microchannel heat exchanger 100 of the embodiment of the invention, as shown in FIGS. 1 and 2, the microchannel heat exchanger 100 comprises: two headers 1, a plurality of heat exchange tubes 2 and at least one fin 3, The two headers 1 are arranged in parallel. Two ends of the plurality of heat exchange tubes 2 are respectively connected to the two header tubes 1, and the plurality of heat exchange tubes 2 are bent along the longitudinal direction thereof (direction indicated by an arrow P in Fig. 1) to form a plurality of tube layers 20.

Specifically, the two headers 1 are spaced apart from each other, and the plurality of heat exchange tubes 2 are bent to form at least two layers 20, each The heat exchange tubes 2 are bent to form one or more pipe segments 21, and one or more pipe segments 21 on the same plane form a parallel in the extending direction parallel to the direction of the headers 1 (the direction indicated by the arrow M in Fig. 1). Tube layer 20. Alternatively, a plurality of heat exchange tubes 2 are arranged in parallel along the extending direction of the header 1 shown by the arrow M. In the example shown in Figure 1, the plurality of pipe sections 21 of each heat exchange tube 2 comprises a straight section 211 and a curved section 212 between the straight sections 211, the curved section 212 being parallel to the extension of the header 1 The direction (the direction indicated by the arrow M) is curved by a predetermined angle with respect to the straight section 211. In FIG. 1, the bending angle of each curved section 212 is 180 degrees, the lengths of the plurality of heat exchange tubes 2 are equal, the number of times of bending of the plurality of heat exchange tubes 2 is equal, and the plurality of heat exchange tubes 2 are formed by bending. The lengths of the straight sections 211 are equal, and the lengths of the curved sections 212 formed are also equal. A plurality of straight sections 211 of the plurality of heat exchange tubes 2 in the same row constitute a tube layer 20, and when the tube layer 20 of a certain layer is connected with the fins 3, the fins 3 can be connected to the tube layer 20 for replacement. The flat section 211 of the heat pipe 2 is on.

Optionally, the cross-sectional profile of the heat exchange tube 2 is a racetrack shape with two arcs in a straight line, wherein the straight side of the heat exchange tube 2 is parallel to the extending direction of the header 1 (the direction indicated by the arrow M). The fins 3 are connected to the straight sections of the heat exchange tubes 2. For convenience of description, the size of the heat exchange tube 2 in the extending direction of the header 1 (direction indicated by the arrow M) is the width of the heat exchange tube 2, and the heat exchange tube 2 is said to be perpendicular to the width direction of the heat exchange tube 2. (the direction indicated by the arrow M) and perpendicular to the longitudinal direction of the heat exchange tube 2 (the direction indicated by the arrow P) is the thickness of the heat exchange tube 2, and the thickness direction of the heat exchange tube 2 is indicated by the arrow Q in FIG. direction. In Fig. 1, the width of the heat exchange tube 2 is larger than the thickness of the heat exchange tube 2.

Specifically, each of the fins 3 is disposed between the adjacent two tube layers 20 or outside the tube layer 20 of the outermost layer, where the fins 3 may be one or more. In a specific example of the present invention, as shown in FIG. 1, a plurality of fins 3 are provided, and one fin 3 is disposed between each adjacent two tube layers 20, and the outermost one of the plurality of tube layers 20 The outer side of the tube layer 20 is also provided with fins 3, respectively. The microchannel heat exchanger 100 is a multi-layer heat exchanger in which the heat exchangers connect the layers 20 of the layers through the fins 3.

Specifically, each fin 3 extends in a corrugated manner in the extending direction of the heat exchange tube 2 (the direction indicated by the arrow P), and each fin 3 in the extending direction of the header 1 (the direction indicated by the arrow M) Continuously extending, and each fin 3 is connected to at least two heat exchange tubes 2 of the tube layer 20 in which it is located. That is, the fins 3 are corrugated in the longitudinal direction of the heat transfer tubes 2, and the fins 3 are continuously provided in the width direction of the heat exchange tubes 2. Here, it is mentioned that the fins 3 are continuously disposed in the width direction of the heat exchange tubes 2, meaning that the fins are not divided into a plurality of sections and disposed at intervals in the width direction of the heat transfer tubes, that is, the fins are shown at M The direction is uninterrupted.

It can be understood that the fins of most of the microchannel heat exchangers in the prior art are short fins, and the fins are arranged between two adjacent heat exchange tubes, the fin length is small, the gap is small, and the processing is complicated. When the evaporator is used at low temperature, the accumulation speed of the frost layer is fast. When the frost is defrosted, the moisture on the fins is dispersed on the small fins, and the water vapor does not easily accumulate into drops and drip, which is difficult to discharge.

In the embodiment of the present invention, by continuously arranging the fins 3 in the width direction of the heat exchange tubes 2 (direction indicated by the arrow M), not only the processing of the fins 3 is simplified, for example, the entire flat sheets can be processed into wings. Film, low processing cost, It is easy to assemble, and the water vapor on the fins 3 is easy to gather into the drops during the defrosting and is easily discharged along the continuous fins 3, preventing the frost layer from forming ice on the surface of the microchannel heat exchanger 100, thereby ensuring microchannel switching. The heat exchange effect of the heat exchanger 100.

Further, the fins 3 are connected to at least two heat exchange tubes 2 in the width direction of the heat transfer tubes 2, and the plurality of heat exchange tubes 2 are joined together by fins to ensure the structural strength of the microchannel heat exchanger 100.

Optionally, each of the fins 3 is connected to all of the heat exchange tubes 2 in the tube layer 20 in which it is located, and the heat exchange tubes 2 connected to the fins 3 can be integrally connected by the fins 3, and the structure is firm and reliable.

In FIG. 1, the microchannel heat exchanger 100 includes three heat exchange tubes 2, and three heat exchange tubes 2 are bent to form four rows of tube layers 20, and three fins 3 between the four rows of tube layers 20 will The four rows of tube layers 20 are connected together, and the adjacent fins 3 and the three heat exchange tubes 2 in each of the tube layers 20 are connected together, and one of the outermost two tube layers 20 is also provided with a wing. Slice 3. Here, since the tube layers 20 are spaced apart in the direction indicated by the arrow Q, the outermost outer layer of the tube layer 20 refers to the outermost sides of the plurality of tube layers 20 in the direction indicated by Q.

Referring additionally to FIG. 5, the flow area of the partial heat exchange tubes 2 is larger than the flow area of the remaining heat exchange tubes 2.

It can be understood that when the microchannel heat exchanger is operated, the heat exchange tube on the windward side is in contact with the air return air first, and the temperature difference between the refrigerant and the outside air is the largest, so the heat exchange amount is large and the heat exchange is relatively sufficient. However, in the heat exchange tube with the most heat transfer, the two-phase section and the superheating section are long, and the refrigerant flow resistance is large. In the refrigerant distribution process, the heat exchange tube with the most heat exchange is easy to be small, and the refrigerant flow rate is easy to be small. The characteristics of the large heat exchange here are contradictory.

In the present invention, the flow area of the partial heat exchange tube 2 is designed to be large, and then the heat exchange tube 2 is disposed at a position where the microchannel heat exchanger 100 can first exchange heat with the blown air. The pressure drop of the refrigerant flowing through the heat exchange tube 2 is reduced, thereby increasing the refrigerant flow rate of the heat exchange tube 2, thereby increasing the heat exchange amount here. In this way, the refrigerant flow rate of the plurality of heat exchange tubes 2 can be made uniform, so that the refrigerant is uniformly distributed in the plurality of heat exchange tubes 2 as much as possible, and the overall heat exchange amount of the heat exchanger is improved.

According to the microchannel heat exchanger 100 of the embodiment of the present invention, by providing the fins 3 on the outer side of the adjacent tube layer 20 or the outermost tube layer 20, each of the fins 3 is corrugated in the extending direction of the heat exchange tubes 2. Extending, each fin 3 extends continuously in the extending direction of the header 1, so that during the defrosting process of the microchannel heat exchanger 100, the frosted water on the surface of the fin 3 can accumulate into water droplets, and the water droplets can be continuous along the wings. The sheet 3 smoothly slides down and drains, solving the problem that the surface of the fin 3 has a large amount of water hanging and cannot be exhausted, and can prevent the ice on the surface of the microchannel heat exchanger 100 from affecting the heat exchange efficiency. By setting the flow area of the partial heat exchange tubes 2 to be larger than the flow area of the remaining heat exchange tubes 2, the heat exchange tubes 2 can be disposed at the first windward side of the microchannel heat exchanger 100, thereby promoting a plurality of heat exchanges. The refrigerant flow rate of the tube 2 is uniform, and the overall heat exchange amount of the heat exchanger is improved.

In some embodiments, in the extending direction of the header 1 (direction indicated by the arrow M), the flow areas of the plurality of heat exchange tubes 2 are sequentially increased or decreased sequentially, and each adjacent two heat exchange tubes 2 The flow area of the heat exchange tube 2 on the windward side is larger than the flow area of the heat exchange tube 2 on the leeward side.

Such a microchannel heat exchanger 100 sets a difference in the flow area of the heat exchange tubes 2 through the refrigerant layers of each layer, thereby reducing the difference in pressure drop loss of the heat exchange tubes of each layer, and finally achieving further promotion of the refrigerant in a plurality of exchanges. The heat pipe 2 is evenly distributed, thereby further increasing the overall heat exchange capacity of the heat exchanger.

In a specific example, as shown in FIG. 5, there are three heat exchange tubes 2, and the microchannel heat exchanger 100 includes a first heat exchange tube 201, a second heat exchange tube 202, and a third heat exchange tube from bottom to top. 203, the ratio of the overflow area of the three heat exchange tubes 2 is 4:3:2, wherein the air flow is blown from below to the heat exchanger when the heat exchanger is in operation, and the flow passage area of the first lower heat exchange tube 201 is the largest. The flow passage area of the uppermost third heat exchange tube 203 is the smallest.

Specifically, as shown in FIG. 5, a plurality of refrigerant flow passages 210 may be defined in each of the heat exchange tubes 2, and the cross-sectional area of the flow passages 210 in each heat exchange tube 2 and the flow passage 210 may be changed. The amount, etc., to change the flow area of each heat exchange tube 2, so that the pressure drop of each flow path in the heat exchange process is basically the same, to maximize the liquid separation uniformity and improve the heat transfer performance.

It can be understood that the number of the heat exchange tubes 2 can be varied according to actual needs, and the ratio of the flow area of each heat exchange tube 2 can also be adapted to the actual situation.

In some embodiments, as shown in FIGS. 1 and 3, at least one of the fins 3 includes a first fin segment 31 and a second fin segment 32, in the direction of extension of the header 1 (direction indicated by arrow M) The size h1 of one fin segment 31 is larger than the size h2 of the second fin segment 32. Here, the fins 3 are arranged to be long and short, corresponding to the formation of a notch in the fins 3. The second fin segments 32 are shorter than the first fin segments 31 to form the above-mentioned notches, and the notches are provided as microchannel heat exchangers. 100 Design structure optimized for frosting and defrosting characteristics.

In particular, when the microchannel heat exchanger 100 is used to output a cooling capacity, air may be blown from the notch of the corresponding microchannel heat exchanger 100 to the microchannel heat exchanger 100. Since the humidity is lowered after the air absorbs the cold amount, the moisture in the air easily condenses on the surface of the microchannel heat exchanger 100 to form a frost layer. After the air is blown from the gap, there is no blockage of the fins 3 at the notch, and the air can be easily blown into the inner tube layer 20 of the microchannel heat exchanger 100, thereby increasing the distribution space of the frost layer and reducing the wing. The amount and speed of frost layer accumulation at the bottom of the sheet 3 reduces the influence of frost on the performance of the microchannel heat exchanger 100 and prolongs the defrosting cycle.

Specifically, as shown in FIGS. 1 and 3, each of the fins 3 includes at least two first fin segments 31 and/or at least two second fin segments 32 in the extending direction of the heat exchange tubes 2 (arrow P In the direction shown), the first fin segment 31 and the second fin segment 32 are staggered. In this way, on the one hand, the structural strength of the fins 3 is prevented from being lowered, and on the other hand, the gaps on the fins are spaced apart, which is advantageous for the microchannel heat exchanger 100 to disperse the frost layer during frosting, thereby enabling quicker defrost during defrosting.

Further, when the fins 3 are plural, the second fin segments 32 on the plurality of fins 3 are correspondingly disposed. That is, when there are a plurality of fins 3, the projection shapes of the plurality of fins 3 are substantially the same in the plane on which the tube layer 20 is located, and each of the fins 3 forms a notch at the same position. Thus, the positions of the notches of the plurality of fins 3 are uniform, thereby improving the microchannel While the heat exchange efficiency of the heat exchanger 100 is increased, the distribution space of the frost layer can be further increased, and the amount and speed of accumulation of the frost layer at the bottom of the fin 3 can be reduced.

Alternatively, as shown in FIG. 3, in the extending direction of the header 1 (direction indicated by the arrow M), the dimension h2 of the second fin segment 32 is 0.67-0.75 of the dimension h1 of the first fin segment 31, also That is, the second fin segment 32 is shorter by 1/4-1/3 than the first fin segment 31 in the extending direction of the header 1.

It can be understood that if the second fin segment 32 is too short, the connection strength of the fin 3 to the tube layer 2 at the second fin segment 32 will be weakened, and if the second fin segment 32 is too long, air will be formed. Obstruction, after comprehensive consideration, it is preferable that the size h2 of the second fin segment 32 is 0.67-0.75 of the dimension h1 of the first fin segment 31, which can ensure that the fin 3 can smoothly discharge the defrosting water in all the segments, and at the same time ensure the frost at the time of entering the wind. The layers can be evenly distributed.

In some embodiments, as shown in FIG. 1, the first fin segment 31 and the second fin segment 32 of each fin 3 are connected to all of the heat exchange tubes 2 in the tube layer 20 in which they are located.

Since the adjacent two heat exchange tubes 2 are spaced apart, after all the heat exchange tubes 2 are connected by the fins 3, the defrosted water on the fins 3 does not fall on the intermediate heat exchange tubes 2, The channel heat exchanger 100 easily drains the defrosting water.

Specifically, as shown in FIG. 4, in the extending direction of the header 1 (direction indicated by the arrow M), the windward side of the second fin segment 32 and the outermost heat exchange tube 2 on the tube layer 20 where it is located The contact size m between the electrodes is 5-10 mm. That is to say, even if the fins 3 are notched, the fins 3 form a joint fit with the outermost heat exchange tubes 2 at the portions of the notched edges.

The second wing segment 32 is designed such that the contact dimension m between the windward side and the outermost heat exchange tube 2 is 5-10 mm, ensuring that it is connected to the outermost heat exchange tube 2, preventing the fins from being suspended when the fins 3 are suspended. The water droplets on the sheet 3 cannot flow down to the outermost heat exchange tubes 2.

In some embodiments, the tube layer 20 of the microchannel heat exchanger 100 is disposed vertically and the plurality of tube layers 20 are spaced apart in a horizontal direction. Each of the fins 3 extends in a corrugated manner in the horizontal direction, and each of the fins 3 continuously extends in the vertical direction. The fins 3 are flush at the upper end, the fins 3 are notched at the lower end, and the fins 3 are divided into a first fin segment 31 and a second fin segment 32, wherein between the second fin segment 32 and the lowermost heat exchange tube 2 The contact height m is 5-10 mm, and an interference fit is formed between the fin 3 and the lowermost heat exchange tube 2.

Further, as shown in FIG. 1, in the extending direction of the heat exchange tube 2 (the direction indicated by the arrow P), each of the fins 3 extends in a zigzag shape, as shown in FIG. 3, the gap between adjacent teeth. n is 5-10 mm. The interdental gap n of the fins 3 is substantially the same, and the ratio of the inter-tooth gap n of each of the fins 3 is between 110% and 90%.

In summary, the microchannel heat exchanger 100 according to the embodiment of the present invention is optimized according to the characteristics of frosting and defrosting on the heat exchanger, and the lengths of the fins 3 and the fins 3 passing through the multilayered tube layer 20 are different. The interference fit between the fin 3 and the outermost heat exchange tube 2 of the tube layer 20 and the differential design of the flow area of different heat exchange tubes slow down the influence of the frost layer accumulation on the surface of the heat exchanger on the operation of the system. At the same time, it is beneficial to drain the defrosting water and increase the flow of the refrigerant. Uniformity, improve heat transfer performance.

A refrigerator (not shown) according to an embodiment of the present invention includes a microchannel heat exchanger 100 according to the above embodiment of the present invention. Alternatively, the microchannel heat exchanger 100 can be used as a refrigerator of a refrigerator or an evaporator of a greenhouse. The structure of the microchannel heat exchanger 100 has been described by the above embodiments, and will not be described herein.

According to the refrigerator of the embodiment of the present invention, by providing the above-mentioned microchannel heat exchanger 100, it is advantageous to exhaust the defrosting water on the microchannel heat exchanger 100 during defrosting, and prevent the ice on the surface of the microchannel heat exchanger 100 from being affected by the ice. Thermal efficiency.

In an air-cooled refrigerator, the air-cooled refrigerator defines a refrigerating compartment and a duct, the duct having a return air for introducing air from the refrigerating compartment, and the air-cooling refrigerator includes the fin 3 according to the present invention including the first fin section 31 And the microchannel heat exchanger 100 of all embodiments of the second fin segment 32.

The structure of the microchannel heat exchanger 100 has been described by the above embodiments, and will not be described herein. The microchannel heat exchanger 100 can be used as a refrigerating chamber of an air-cooled refrigerator or an evaporator of a greenhouse. The microchannel heat exchanger 100 is disposed in the air duct, and the microchannel heat exchanger 100 can be arranged above the air return port of the refrigerating chamber or the greenhouse. The short second fin segment 32 has a longer first fin segment 31 disposed at other locations.

Specifically, in the air channel microchannel heat exchanger 100, two headers 1 are vertically disposed, and the second fin segments 32 of the fins 3 are disposed above the return air vents. That is to say, when the air-cooled refrigerator is cooling, the indoor air in the cooling room is blown from the return air port to the air passage, and the blown air is blown into the microchannel heat exchanger 100 from the bottom of the microchannel heat exchanger 100.

The portion of the fin 3 that is shorter than the first fin segment 31 in the second fin segment 32 corresponds to a notch, and air can be blown from the notch of the corresponding microchannel heat exchanger 100 toward the microchannel heat exchanger 100. After the air absorbs the cold amount, the humidity is lowered, and the water vapor in the air is easily condensed on the surface of the microchannel heat exchanger 100 to form a frost layer. Since air is blown from the notch to the microchannel heat exchanger 100, air can be easily blown between the inner tube layers 20 of the microchannel heat exchanger 100 after the blockage of the fins 3, thereby increasing the frost layer. The distribution space reduces the accumulation amount and speed of the frost layer at the bottom of the fin 3, reduces the influence of the frost on the performance of the microchannel heat exchanger 100, and prolongs the defrosting cycle.

Specifically, the horizontal width w (marked in FIG. 3) of the second fin segment 32 is substantially 1.1-1.4 times the horizontal width of the return air vent, so that the fin 3 can be avoided as far as possible from the return air vent, and the return air is blown off. To the inside of the microchannel heat exchanger 100.

Further, when the fins 3 are provided on the outermost tube layer 20 of the microchannel heat exchanger 100, the outermost fins 3 of the microchannel heat exchanger 100 are directly barely leaked, and there is no shield on the outer side of the fins 3. protection. That is to say, the outermost fin 3 is not connected to other components, and there is no protective device to reduce the contact with the tank of the refrigerating compartment and the cover of the heat exchanger, thereby reducing the amount of leakage of the casing and changing The possibility of frost on the surface of the heater cover.

The air-cooled refrigerator according to the embodiment of the present invention has the following features by providing a microchannel heat exchanger designed specifically for a single-cycle air-cooled refrigerator:

1. Use the whole straight fin to connect 3-4 layers of parallel heat exchange tubes to one piece, reduce the amount of water hanging on the fin surface during defrosting, and prevent the surface of the heat exchanger from forming “unstopping ice”;

2. By shortening the length of the fins above the refrigerating chamber and the return air inlet of the greenhouse, reducing the accumulation rate of the frost layer near the return air inlet, reducing the influence of frost layer accumulation on the cold storage room and the greenhouse, and prolonging the defrosting time;

3. The lower edge of the fin 3 extends into or out of the adjacent heat exchange tube 5-10mm, which facilitates the downward flow of the defrosting water to prevent water droplets from accumulating at the ends of the fin;

4. The fins 3 on both sides are directly barely leaked, and there is no protective layer, reinforcing plate or support plate, which reduces the leakage of the protective layer and the tank and the possibility of frosting of the heat exchanger cover;

5. The cross-sectional area of the microchannels in the upper, middle and lower parallel heat exchange tubes 2 are designed to be different, and the ratio is approximately 2:3:4. By changing the flow area of the heat exchange tubes, the flow paths are The pressure drop in the heat exchange process is basically the same, the liquid separation uniformity is increased as much as possible, and the heat transfer performance is improved;

6. The design solves the frosting and defrosting problems of the microchannel heat exchanger used in the air-cooled refrigerator. On the basis of ensuring the efficient operation of the heat exchanger, according to the heat transfer characteristics of the air-cooled refrigerator heat exchanger, the common micro The channel heat exchanger is optimized to improve system efficiency and achieve energy saving.

It can be understood that the refrigerator is also provided with components of other refrigeration systems such as a compressor and a condenser. The structure and working principle of the refrigeration system are already prior art, and the connection structure of the microchannel heat exchanger 100 in the refrigeration system of the refrigerator is also It has been an existing technology and will not be described here.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "height", "upper", "lower", " The orientation or positional relationship of the front, rear, rear, left, right, top, bottom, inner, and outer directions is based on the drawing The orientation or positional relationship shown is for the purpose of describing the present invention and the simplified description, and is not intended to indicate or imply that the device or component referred to has a particular orientation, is constructed and operated in a particular orientation, and thus is not to be construed as a limits.

Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include one or more of the features either explicitly or implicitly. In the description of the present invention, "a plurality" means two or more unless otherwise stated.

While the embodiments of the present invention have been shown and described, the embodiments of the invention may The scope of the invention is defined by the claims and their equivalents.

Claims

A microchannel heat exchanger, comprising:

Two headers, the two collectors being arranged in parallel;

a plurality of heat exchange tubes, wherein two ends of the plurality of heat exchange tubes are respectively connected to the two current collecting tubes, and the plurality of heat exchange tubes are bent along a length thereof to form a plurality of tube layers, and the heat exchange portion The flow area of the tube is greater than the flow area of the remaining heat exchange tubes;

At least one fin, each of the fins being disposed between adjacent two of the tube layers or outside the tube layer disposed at the outermost layer, each of the said heat exchange tubes extending in the direction The fins extend in a corrugated shape, and each of the fins extends continuously in the extending direction of the header.
The microchannel heat exchanger according to claim 1, wherein the flow area of the plurality of heat exchange tubes is sequentially increased or decreased sequentially in the extending direction of the header, and each adjacent two The flow area of the heat exchange tubes on the windward side of the heat exchange tubes is larger than the flow area of the heat exchange tubes located on the leeward side.
The microchannel heat exchanger according to claim 1 or 2, wherein the heat exchange tubes are three, and the flow areas of the three heat exchange tubes are in the extending direction of the header The ratio is 2:3:4.
A microchannel heat exchanger according to any one of claims 1 to 3, wherein at least one of said fins comprises a first fin segment and a second fin segment in the direction of extension of said header The size of the first fin segment is greater than the size of the second fin segment.
The microchannel heat exchanger according to claim 4, wherein said second fin segment has a size of 0.67 to 0.75 of a size of said first fin segment in an extending direction of said header.
A microchannel heat exchanger according to claim 4 or 5, wherein each of said first fin segment and said second fin segment in each of said fins is in the same layer as said tube layer The heat exchange tubes are connected.
The microchannel heat exchanger according to any one of claims 4-6, wherein the windward side of the second fin segment and the tube in which it is located in the extending direction of the header The contact dimension between the outermost heat exchange tubes on the layer is 5-10 mm.
An air-cooled refrigerator, wherein the air-cooled refrigerator defines a refrigerating compartment and a duct, the duct having a return air inlet for entering air from the refrigerating compartment, wherein the air-cooling refrigerator includes rights according to rights The microchannel heat exchanger of any of claims 1-7.
The air-cooled refrigerator according to claim 8, wherein the microchannel heat exchanger is the microchannel heat exchanger according to any one of claims 4-7, wherein the microchannel heat exchanger is provided Within the air duct, the two headers are vertically disposed, and the second fin segments of the fins are disposed above the return air vents.
The air-cooled refrigerator according to claim 9, wherein the horizontal width of the second fin segment is substantially 1.1 to 1.4 times the horizontal width of the corresponding air return port.