WO2012100490A1

WO2012100490A1 - Condenser

Info

Publication number: WO2012100490A1
Application number: PCT/CN2011/075862
Authority: WO
Inventors: 刘迎文; 刘冈云; 童欢; 徐升华; 胡露露
Original assignee: 西安交通大学
Priority date: 2011-01-26
Filing date: 2011-06-17
Publication date: 2012-08-02
Also published as: CN102052807A; CN102052807B

Abstract

Disclosed is a condenser which includes a radiating back plate (2) and a number of porous micro-channel heat exchange flat pipes (3) arranged at the inner side of the radiating back plate (2). A heat insulating foam layer (1) tightly presses a number of the heat exchange flat pipes (3) against the inner side of the radiating back plate (2). A number of parallel channels (4) are provided in the heat exchange flat pipes (3) in the way that they share the same fluid flow direction, and form an over-temperature cooling section (a), a two-phase condensing section (b) and a below-temperature cooling section (c) of the condenser. The area of flow cross section remains constant within each section but shrinks from the over-temperature cooling section (a) to the two-phase condensing section (b) and to the below-temperature cooling section (c) in a stepwise manner. The condenser is compact and has a high heat exchange efficiency and economic advantage.

Description

a condenser

Technical field

The invention belongs to the field of ordinary household refrigeration, and particularly relates to a built-in condenser suitable for a refrigeration device such as a general refrigerator or a freezer.

Background technique

Refrigerators and freezers are the only all-day power-consuming items in household appliances, which give people a comfortable life while consuming a lot of power. China's household refrigerator power consumption limit value and energy efficiency rating

(GB12021. 2-2008) » The introduction, it has been mandatory to carry out technical transformation and innovation on the refrigerator, hoping to be more energy efficient. From the perspective of the refrigeration system, the condenser is responsible for the outward heat dissipation and has the largest thermal load, so it is one of the main components that need to strengthen energy conservation research. The existing refrigerator condenser is mainly built-in plate type, for example: Chinese patent 200520017276. 7, the condensation of the condensation tube and the steel plate (ie the side plate of the refrigerator), in theory, the contact can only be a line, if the tube is vertical Degree or plate flatness can not be guaranteed, or even a "virtual" line, which increases the heat transfer resistance and affects the heat transfer performance. In addition, there are some improvements in the heat transfer tube type, for example: "D" type tube used in Chinese patent 200920186647. 2, Japanese patent JP19910048374 uses an elliptical tube, so that the contact area between the heat exchange tube and the refrigerator back plate is The increase is still larger than the outer surface area of the tube, and the wet period in the tube is small, and the heat exchange area is small.

In addition, the leakage heat from the condenser to the inside of the refrigerator is also one of the important loads of the refrigerator. In the tank wall condenser, the heat transferred to the inside of the refrigerator through the foam layer accounts for about 12% of the total load of the condenser, thereby improving the refrigerator cabinet. Thermal insulation is critical. At present, the use of vacuum insulation, high-performance insulation materials and other technologies, only one step to reduce heat loss, but these technologies have undoubtedly increased the manufacturing cost and process complexity of the product, can not be widely applied. A microchannel heat exchanger, usually referred to as a heat exchanger having a heat exchanger channel equivalent diameter of 10 to 1000 μm. The heat transfer basics of microchannel heat exchangers are different from conventional heat exchangers. Surface roughness, fluid viscosity and runner geometry all have important effects on heat transfer. When the equivalent diameter of the cross section of the flow passage is as small as 0.5 to 1 匪, the convective heat transfer coefficient can be increased by 50%. When the structure, process and heat transfer measures of the heat exchanger are changed, the heat transfer can be effectively enhanced. The heat transfer of the heater increases its energy efficiency ratio. Because of its high heat transfer coefficient, it requires a short process and several parallel processes, so its pressure drop can also be reduced. Since the 1980s, microscale heat transfer has received extensive research and attention. With the study of micro-scale heat transfer, microchannel heat exchangers have been continuously developed. At present, microchannel heat exchangers are mainly used in electronic device cooling, automotive air conditioning, etc. The application in home air conditioning systems is also under research and evaluation, and the application on the refrigerator has not been involved.

Chinese patent CN200410009949. 4 introduces a plate-and-tube condenser for a micro-channel refrigerator. Unlike the existing serpentine tube, it adopts the structure of upper and lower headers and vertical tube bundles, superheated steam from the upper header entering the condenser. Then, the convection heat transfer through the plate is convectively condensed in the downward flow process, and condenses into a supercooled liquid when entering the lower header, and enters the throttling mechanism. The tube bundle is directly welded to the heat dissipation plate, which reduces the diameter of the heat exchange tube, and not only solves the excessive pressure drop caused by the excessive length of the serpentine tube, but also enhances the heat exchange inside the tube due to the reduction of the inner and outer diameter of the tube. Significant savings in materials. However, the channel size of the patent is more than 3 inches, and the heat transfer process of the "line" contact of the built-in condenser has not been completely changed, and the heat transfer efficiency is affected.

Summary of the invention

The object of the present invention is to provide a heat transfer mode capable of completely overcoming the design defect of the existing built-in condenser, that is, the "line" contact heat transfer mode, realizing the "face" contact in the true sense, and further improving the heat dissipation performance. Moreover, the refrigeration efficiency of the refrigerator and the freezer is effectively improved, and the condenser structure form of the system energy saving is realized. In order to achieve the above object, the technical solution adopted by the present invention comprises: a heat dissipation back plate and a plurality of porous microchannel heat exchange flat tubes disposed on the inner side of the heat dissipation back plate, and a plurality of porous microchannel heat exchange flat tubes insulated by the foam layer Pressing into the inner side of the heat dissipation backing plate, the porous microchannel heat exchange flat tube has a plurality of parallel passages in the same fluid flow direction, and the plurality of porous microchannel heat exchange flat tubes constitute the superheated cooling section of the condenser. The two-phase condensation section b and the supercooling cooling section c have the same flow cross section of each section, but the flow cross section from the superheated cooling section a to the two-phase condensation section b and the supercooled cooling section c changes from large to small.

The porous microchannel heat exchange flat tube of the superheated cooling section a, the two-phase condensation section b and the supercooled cooling section c constituting the condenser of the present invention is connected through the header, and the number of parallel channels of the heat transfer flat tubes of the porous microchannels in each section From the superheated cooling section a, the two-phase condensation section b and the supercooled cooling section c are decremented.

The porous microchannel heat exchange flat tubes of the superheated cooling section a, the two-phase condensation section b and the supercooled cooling section c constituting the condenser are arranged in parallel, and the sections are disposed on both sides of the porous microchannel heat exchange flat tube The distribution pipe and the liquid collection pipe are connected to each other, and the distribution pipe and the liquid collection pipe are respectively equipped with a baffle for changing the size of the flow cross section of each section to make the superheated cooling section a to the two-phase condensation section b, too cold The flow cross section of the cooling section c is decreasing.

Another technical solution of the present invention is: comprising a heat dissipating back plate, wherein a plurality of two-stage porous microchannel heat exchange flat tubes arranged in parallel vertically are arranged inside the heat dissipating back plate, and the heat insulating foam layer is arranged in a plurality of parallel vertical The two-stage porous microchannel heat exchange flat tube is pressed to the inner side of the heat dissipation back plate, and the porous microchannel heat exchange flat tube has a plurality of parallel channels along the same fluid flow direction, and the first-stage porous microchannel heat exchange is flat The inlet end of the tube is in communication with the distribution tube, and the outlet end of the second-stage porous microchannel heat exchange flat tube is connected to the liquid collecting tube, and the number of the first-stage microchannel heat-exchange flat tubes is greater than that of the second-stage micro-channel heat exchange The number of flat tubes, the outlet of the first-stage porous microchannel heat exchange flat tube is connected to the inlet of the second-stage porous microchannel heat exchange flat tube through the gas-liquid separation tube, and the second-stage porous microchannel heat exchange is flat The tube is divided into a liquid guiding tube d and a gas guiding tube e according to the height of the gas-liquid separation tube, and the liquid guiding tube d is just right. It is connected to the lowest end of the gas-liquid separation pipe, and the gas guiding pipe e is higher than the bottom of the gas-liquid separation pipe.

The porous microchannel heat exchange flat tube adopts a flat tube whose width is larger than the thickness thereof, and the parallel passage adopts a circular section, a square section or a profiled section.

The parallel passages of the porous microchannel heat exchange flat tubes are also provided with internal teeth for enhancing heat exchange. The plurality of porous microchannel heat exchange flat tubes are closely attached to the inner side of the heat dissipation backing plate by the thermal grease. The outer surface of the heat dissipation back plate is further provided with an expansion fin that increases the heat exchange area.

The heat exchange tube of the invention adopts a porous microchannel flat tube structure, and divides the flow passage of the refrigerant into a plurality of parallel micro-diameter flow passages, thereby greatly improving the convective heat transfer coefficient in the tube, and the width of the porous microchannel flat tube is large In the thickness, the heat exchange flat tube is closely attached to the heat dissipation back plate with its width surface, which greatly expands the contact area between the heat exchange tube and the heat dissipation back plate, and the heat exchange tube has nearly 50% external surface area and direct contact with the heat dissipation back plate, thereby improving The average temperature of the side wall of the refrigerator increases the heat exchange temperature difference. At the same time, by increasing the radiation heat transfer coefficient, the total heat transfer coefficient outside the heat dissipation back plate is improved. At the same time, since the thickness of the porous microchannel flat tube is small, this means that the interlayer thickness increases the thickness of the foam insulation material without changing the size of the inner tank storage space of the existing refrigeration equipment, thereby greatly reducing The leakage heat loss of the refrigeration equipment increases the cooling efficiency; on the contrary, if the thickness of the foam insulation material is maintained, it means that the storage capacity of the inner tank of the refrigeration equipment is enlarged, thereby increasing the internal contents of the refrigeration equipment. The amount of storage.

DRAWINGS

Figure 1 is a basic structural view of the present invention;

2 is a temperature distribution diagram of the heat dissipation back plate in the direction of the vertical heat exchange tube of the present invention;

Figure 3 is a schematic structural view of Embodiment 1 of the present invention;

Figure 4 is a schematic structural view of Embodiment 2 of the present invention;

Figure 5 is a schematic structural view of Embodiment 3 of the present invention; Figure 6 is a schematic structural view of Embodiment 4 of the present invention;

Figure 7 is a partial enlarged view of Figure 6 of the present invention.

detailed description

The structural principle and working principle of the present invention will be further described in detail below with reference to the accompanying drawings.

Embodiments Referring to FIG. 1 and FIG. 3, the embodiment includes a heat dissipation backing plate 2 and a plurality of porous microchannel heat exchange flat tubes 3 which are closely attached to the inner side of the heat dissipation back plate 2 by a thermal grease. The outer surface of the heat dissipation back plate 2 can be disposed. The expanding fin 10 for increasing the heat exchange area, the heat-resistant silicone grease of the invention reduces the contact thermal resistance, and the heat-insulating foam layer 1 presses a plurality of porous microchannel heat-exchange flat tubes 3 to the inner side of the heat-dissipating back plate 2 The porous microchannel heat exchange flat tube 3 has a plurality of parallel channels 4 having a circular cross section, a square cross section or a profiled cross section having an equivalent diameter of 0.8 to 1.2 沿 in the same fluid flow direction. In order to enhance heat exchange, the present invention can also add internal teeth in the parallel passage 4. The plurality of porous microchannel heat exchange flat tubes 3 constitute a superheated cooling section a of the condenser, a two-phase condensation section b and a supercooled cooling section c, a superheated cooling section a, a two-phase condensation section b and a supercooled cooling section c The porous microchannel heat exchange flat tube 3 is connected via the header 5, and the number of parallel channels 4 of each section of the porous microchannel heat exchange flat tube 3 decreases from the superheated cooling section a to the two-phase condensation section b and the supercooled cooling section c. In the embodiment, a porous microchannel heat exchange flat tube 3 having a larger width and a larger number of holes is used in the superheating section, and a porous microchannel heat exchange flat tube having a smaller width and a smaller number of holes is used in the two-phase section and the supercooling section. 3, to adapt to the specific volume change of the refrigerant. For the case where the refrigerant flow rate is low, it is also possible to use only a flat tube of one structure.

The working process is as follows:

As shown in FIG. 3, the high temperature and high pressure refrigerant vapor from the compressor enters the superheated cooling section a of the porous microchannel flat tube condenser 3, is cooled to a saturated gas, and then enters the porous microchannel flat tube condenser 3 through the header 5. After the two-phase condensation section b is condensed to a saturated liquid, it enters the supercooling cooling section c of the porous microchannel flat tube condenser 3 through the header 5, and is cooled to the necessary degree of subcooling to enter the throttling device. Embodiment 2: Referring to FIG. 4, the embodiment includes a heat dissipating back plate 2 and a plurality of porous microchannel heat exchange flat tubes 3 which are closely adhered to the inner side of the heat dissipating back plate 2 by a thermal grease, and the heat insulating foam layer 1 has a plurality of layers. The singularity of the same direction of the same fluid flow direction is 0. 8 - 1. 2mm, the porous microchannel heat exchanger flat tube 3 has a plurality of equivalent diameters in the same fluid flow direction of 0. 8 - 1. 2mm Parallel channel 4 of circular section, square section or profiled section. The porous microchannel heat exchange flat tubes 3 constituting the superheated cooling section a, the two-phase cooling section b and the supercooled condensing section c of the condenser are arranged in parallel horizontally, and the sections are disposed on both sides of the porous microchannel heat exchange flat tube 3 The distribution pipe 6 and the liquid collection pipe 7 are in communication, and the distribution pipe 6 and the liquid collection pipe 7 are respectively equipped with a baffle 8 for changing the size of each section of the flow passage so that the superheated cooling section a is two The flow cross section of the phase condensation section b and the supercooling section c decreases.

Embodiment 3 Referring to Figure 5, the porous microchannel heat exchange flat tubes 3 of the superheated cooling section a, the two-phase condensation section b and the supercooled cooling section c which constitute the condenser are vertically arranged in parallel. The other connection relationship is the same as in Embodiment 2.

Referring to Figures 4 and 5, the high temperature and high pressure refrigerant vapor from the compressor first enters the distribution pipe 6, enters the porous microchannel flat tube condenser 3 under the action of the baffle 8, and then enters the liquid collection tube 7, due to the refrigerant at this time. For superheated steam, the specific volume is larger, so after using more porous microchannel flat tube condenser 3 to cool to saturated gas, the position of the baffle 8 in the distribution pipe 6 and the liquid collecting pipe 7 is changed, and less porous is adopted. The microchannel flat tubes are arranged in parallel to ensure that the refrigerant has a sufficiently large flow velocity in the porous microchannel flat tube. After condensing to the saturated liquid, the specific volume of the refrigerant is greatly reduced. At this time, in order to ensure the flow rate of the refrigerant in the tube, the flow rate is adopted. There are fewer heat exchange tubes, and finally the refrigerant flows out of the condenser through the header 7.

Embodiment 4: Referring to FIG. 6, the embodiment includes a heat dissipation backplane 2, and a plurality of two-stage porous microchannel heat exchange flat tubes 3 arranged in parallel vertically are disposed inside the heat dissipation backboard 2, and the heat insulation foam layer 1 will be a plurality of parallel two-stage porous microchannel heat exchange flat tubes 3 are pressed into the inner side of the heat dissipation backing plate 2, and the porous microchannel heat exchange flat tubes 3 have a plurality of parallel passages 4 along the same fluid flow direction. Said The inlet end of the first-stage porous microchannel heat exchange flat tube 3 is in communication with the distribution tube 6, and the outlet end of the second-stage porous microchannel heat exchange flat tube 3 is in communication with the liquid collecting tube 7, due to the upper refrigerant dryness Large, specific volume is gradually increased, and the porous microchannel heat exchange flat tube 3 with more tube bundles can ensure sufficient heat transfer and reduce flow resistance. As the refrigerant is continuously condensed, its dryness is more and more Small, the specific volume gradually decreases. In order to ensure that the refrigerant has sufficient flow rate to increase the heat transfer coefficient, a smaller number of porous microchannel heat exchange flat tubes 3 are used; the first stage porous microchannel heat exchanger flat tube 3 outlet The gas-liquid separation tube 9 is connected to the inlet of the second-stage porous microchannel heat exchange flat tube 3. Referring to FIG. 7, the second-stage porous microchannel heat exchange flat tube 3 is extended into the gas-liquid separation tube 9. The height is divided into a liquid guiding tube d and a gas guiding tube e, the liquid guiding tube d is just connected to the lowest end of the gas-liquid separation tube 9, and the gas guiding tube e is higher than the bottom of the gas-liquid separation tube 9, the liquid guiding The difference in the arrangement height between the flow tube d and the gas guide tube e realizes the presence of gas and liquid Separation, to further improve the heat transfer characteristics.

The high temperature and high pressure refrigerant vapor from the compressor flows through the first stage porous microchannel heat exchange flat tube 3 through the distributor 6 and exchanges heat, and when the intermediate gas liquid separation tube 9 is reached, the refrigerant is in a two-phase state. Due to the action of gravity, gas-liquid stratification occurs, and the liquid flows down the liquid guiding tube d. The gas flows down along the gas guiding tube e and condenses, and the collecting pipe 7 merges and discharges. Since the secondary diversion is adopted, the refrigerant condensation is avoided. The influence of the liquid film on the condensation heat transfer, because the existence of the liquid film hinders the contact chance of the refrigerant vapor and the wall surface, thereby reducing the condensation heat transfer coefficient, and the invention can effectively weaken the influence and further improve the heat transfer characteristics.

Referring to FIG. 2, after implementing the present invention, under the premise that the ambient temperature, the size of the heat dissipation backplane structure and the pipe spacing are constant, the temperature distribution trend of the existing plate-and-tube condenser heat dissipation back plate may be changed, that is, the average When the temperature rises, the extent of the increase will gradually increase with the increase of the width of the flat tube. According to the principle of heat transfer, the heat transfer amount is the product of the heat exchange area, the heat transfer temperature difference and the heat transfer coefficient, because the heat transfer area is mainly Depending on the size of the structure, it remains unchanged, and with the present invention, the heat transfer temperature difference is improved. The radiation heat transfer coefficient of one of the compositions of the heat transfer coefficient is increased due to the increase of the average temperature. Therefore, after the invention, the heat dissipation capability of the condenser can be greatly improved, thereby further improving the efficiency of the refrigeration system and saving material costs. .

The porous microchannel heat exchange flat tube 3 of the present invention is closely attached to the heat dissipation back plate 2 by its width width, and the larger "face" contact acts to reduce the heat transfer heat resistance, thereby improving the heat dissipation capability of the condenser.

The above description is only the best embodiment of the present invention, but the structural features of the present invention are not limited thereto, and the present invention can directly replace the box wall condenser which is widely used at present, and can also be used for the refrigeration of the split condenser. Apparatus, the air-side heat transfer form of the outer wall of the heat transfer tube, whether natural or forced convection, or a structural form of a heat transfer extension surface, etc., any variation made by those skilled in the art in the field of the present invention Modifications are encompassed within the scope of the invention.

Claims

Claim

A condenser, comprising: a heat dissipation backplane (2) and a heat dissipation backplane

(2) Several porous microchannel heat exchange flat tubes (3) on the inner side, thermal insulation foam layer (1) Press several porous microchannel heat exchange flat tubes (3) to the inner side of the heat dissipation back plate (2) The porous microchannel heat exchange flat tube (3) has a plurality of parallel passages (4) along the same fluid flow direction, and the plurality of porous microchannel heat exchange flat tubes (3) constitute a superheating cooling of the condenser. Section (a), two-phase condensation section (b) and subcooling cooling section (c), the flow cross sections of each section are the same, but from the superheated cooling section (a) to the two-phase condensation section (b) and the supercooled cooling section ( c) The flow cross section varies from large to small.

The condenser according to claim 1, characterized in that: said superheated cooling section (a), two-phase condensation section (b) and supercooled cooling section (c) of the condenser are exchanged for porous microchannels Hot flat tube

(3) Connected through the header (5), and each section of the porous microchannel heat exchanger flat tube (3) parallel channel (4) from the superheated cooling section (a) to the two-phase condensation section (b), supercooled cooling Paragraph (c) is decremented.

The condenser according to claim 1, characterized in that: said porous microchannel exchange of the superheated cooling section (a), the two-phase condensation section (b) and the supercooled cooling section (c) constituting the condenser The heat flat tubes (3) are arranged in parallel, and the respective sections are connected by a distribution pipe (6) and a liquid collecting pipe (7) disposed on both sides of the porous microchannel heat exchange flat pipe (3), the distribution pipe ( 6) and the liquid collecting pipe (7) are equipped with baffles (8). The baffles (8) are used to change the size of each section of the flow section so that the superheated cooling section (a) is condensed into the two-phase condensation section (b). The flow cross section of the cold cooling section (c) is decreasing.

4. A condenser, comprising: a heat dissipating back plate (2), and a plurality of two-stage porous microchannel heat exchange flat tubes (3) arranged in parallel and vertically disposed on the inner side of the heat dissipating back plate (2), separated by Hot foam layer

(1) A plurality of two-stage porous microchannel heat exchange flat tubes (3) arranged in parallel and vertically are pressed to the inner side of the heat dissipation back plate (2), and there are several along the porous microchannel heat exchange flat tubes (3). Parallel channel (4) of the same fluid flow direction, the inlet end of the first-stage porous microchannel heat exchange flat tube (3) and the distribution tube (6) The outlet end of the second-stage porous microchannel heat exchange flat tube (3) is connected to the liquid collecting tube (7), and the number of the first-stage microchannel heat exchange flat tubes (3) is larger than the second The number of microchannel heat exchange flat tubes (3), the outlet of the first stage porous microchannel heat exchange flat tubes (3) through the gas-liquid separation tube (9) and the second-stage porous microchannel heat exchange flat tubes (3) The inlet of the second stage porous microchannel heat exchange flat tube (3) is divided into a liquid guiding tube (d) and a gas guiding tube according to the height of the gas-liquid separation tube (9). ), the liquid guiding tube (d) is connected to the lowest end of the gas-liquid separation tube (9), and the gas guiding tube (e) is higher than the bottom of the gas-liquid separation tube (9).

The condenser according to claim 1 or 4, wherein: the porous microchannel heat exchange flat tube (3) is a flat tube having a width greater than a thickness thereof, and the parallel passage (4) has a circular cross section. Square section or profiled section.

The condenser according to claim 1 or 4, characterized in that: the parallel passage (4) of the porous microchannel heat exchange flat tube (3) is further provided with internal teeth for enhancing heat exchange.

The condenser according to claim 1 or 4, characterized in that: the plurality of porous microchannel heat exchange flat tubes (3) are adhered to the inner side of the heat dissipation backing plate (2) by a thermal grease.

The condenser according to claim 1 or 4, characterized in that the outer surface of the heat dissipation backing plate (2) is further provided with expansion fins (10) which increase the heat exchange area.