EP2486358B1

EP2486358B1 - Microchannel heat exchanger and the manufacturing method thereof

Info

Publication number: EP2486358B1
Application number: EP10757792.6A
Authority: EP
Inventors: Husnu Kerpicci; Aydin Celik; Onur Poyraz
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2009-10-07
Filing date: 2010-09-29
Publication date: 2017-07-12
Anticipated expiration: 2030-09-29
Also published as: EP2486358A2; WO2011042344A3; WO2011042344A2

Description

The present invention relates to a heat exchanger comprising microchannel tubes whereon fins are mounted.
Nowadays, the use of microchannel tubes in heat exchangers as an alternative to circular tubes has increased with each passing day since they increase the coefficient of heat convection. The microchannels have a rectangular or flat profile. Due to this configuration, the fins to be used on the microchannels require to have a different structure than the fins used on the circular tube heat exchangers.
In the heat exchangers comprising circular tubes, the tube - fin contact is provided by inflating the tubes after the fins are fitted to the tube. This method is not suitable in microchannels since it will damage the structure of the channel. The microchannels, due to their rectangular shaped profiles, can result in the situation wherein the fin contact is not good enough and is not able to use sufficient fin surface. The performance of the heat exchanger is decreased by not providing adequate contact of the fins used on the microchannels with the channel surface.
A heat exchanger according to the preamble of claim 1 is known from document JPS5447153 . In the state of the art Japanese Patent Application No JP8247678 , the fins mounted on a heat exchanger having microchannel tubes are explained.
In the state of the art Japanese Patent Application No JP8197645 , a production method of a heat exchanger is explained. According to this, the fins are equidistantly secured on the microchannel tube by means of an adhesive and thereafter the fins are erected to be vertical to the microchannel tube by applying an electric field.
The aim of the present invention is the realization of a heat exchanger comprising microchannel tube, the performance of which is improved by mounting the fin thereon.
The heat exchanger realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, comprises a tube having at least two microchannels with parallel flow, through which the refrigerant passes, and a retainer formed by bending a sheet, surrounding the bottom, top and a side of the tube and a fin having a plate again formed by bending a sheet, secured to the retainer at the middle such that it will partially surround the retainer, and the ends of which are folded such that there will be an angle between the tube surface and itself.
The fin is mounted to the microchannel tube from one side to be parallel to the plate flow direction.
Consequently, the performance of the heat exchanger is provided to be increased by providing better fin contact on the tube with quadrangular cross section.
In an embodiment of the present invention, the fin is shaped as pincers. Thus, the fin contacts the tube by completely being seated on the surfaces of the tube and clasps the microchannel tube tightly from above and below by itself. This provides ease of both assembly and manufacturing.
The retainer comprises two arms that contact the top and bottom of the tube and a bend that joins these two arms. The tube is compressed from above and below by the arms and remains between the arms. Accordingly, the contact between the tube and the fin is provided in the best possible manner. The plate is secured from its middle portion on the bend and is bent such that it will surround the arms. Since the fin is mounted to the tube by fitting from the side, the necessity for fitting the fins successively to the tube in block form is eliminated.
In another embodiment of the present invention, the heat exchanger comprises a housing. This housing facilitates the assembly of the defrost heater on the heat exchanger.
By means of the present invention, the fin is mounted on the heat exchanger by fitting from one side. Consequently, the performance of the heat exchanger is provided to be increased by providing better fin contact on the tube with quadrangular cross section.
A heat exchanger realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 - is the perspective view of the heat exchanger with the fin mounted thereon.
Figure 2 - is the front view of the heat exchanger with the fin mounted thereon.
Figure 3 - is the perspective view of the fin.
Figure 4 - is the perspective view of the heat exchanger with the fin mounted thereon relating to an embodiment of the present invention.

The elements illustrated in the figures are numbered as follows:

1. Heat exchanger
2. Tube
3. Channel
4. Fin
5. Retainer
6. Plate
7. Bend
8. Housing
9. Arm

The heat exchanger (1) of the present invention comprises a microchannel tube (2), preferably with quadrangular cross section, having channels (3) arranged in order and parallel to each other, through which the refrigerant passes.

The heat exchanger (1), furthermore, comprises:
- a retainer (5) formed by bending a rectangular shaped sheet from the center, mounted on the tube (2) to surround the top, bottom and one side of the tube (2) and
a fin (4) that has a plate (6) which is formed by another rectangular shaped sheet, secured to the retainer (5) at the center, being bent at the middle over the retainer (5) such that it will surround the retainer (5), and which forms a protrusion on the tube (2) surface by lifting at least one end such that there will be an angle between the tube (2) surface and itself (Figure 1 and Figure 2).

Consequently, the performance of the heat exchanger (1) is provided to be increased by providing better fin (4) contact on the tube (2) with quadrangular cross section.
The fin (4) is manufactured from aluminum material and is shaped as pincers. Thus, when the fin (4) is mounted on the tube (2), it clasps the tube (2) tightly. By means of the pincers shaped configuration, the fin (4) - tube (2) contact is provided to be tight by itself. Ease of assembly and manufacturing is provided since an additional operation is not required to be performed for increasing the tube (2) - fin (4) contact after completing the assembly of the fin (4) on the tube (2).
The length of the sheet, from which the plate (6) is manufactured, is equal to the length of the sheet, from which the retainer (5) is manufactured.
The retainer (5) comprises two arms (9) that contact the top and bottom of the tube (2) and a bend (7) that joins these two arms (9). When the fin (4) is mounted on the tube (2) by fitting from its side portion, the tube (2) is compressed from above and below by the arms (9) and remains between the arms (9) due to the pincers configuration. Accordingly, the contact between the tube (2) and the fin (4) is provided in the best possible manner. The plate (6) is secured from its middle portion on the bend (7) and is bent such that it will surround the arms (9). Since the fin (4) is mounted to the tube (2) by fitting from the side, the necessity for fitting the fins (4) to the tube (2) successively in a block is eliminated.
In an embodiment of the present invention, the fins (4) are assembled on the microchannel tube (2) in the following way: Two aluminum sheets, after being overlapped, are secured to one another from their middle portions preferably by adhesion. In this position, the sheet forming the plate (6) is secured from its middle portion to the bend (7) of the sheet forming the retainer (5). Afterwards, the two sheets secured to one another are bent by being pressed from their bends (7) and middle portions. While one of the sheets forms the retainer (5) with pincers configuration that clasps the microchannel tube (2), the other forms the plate (6). Since the retainer (5) carries pressure force on itself, the arms (9) apply pressure on the microchannel tube (2) when this pincers shaped configuration is fitted on the surface of the microchannel tube (2) and the tube (2) - fin (4) contact is provided tightly by itself. Thus, an additional operation is not required for improving the tube (2) - fin (4) contact. Thereafter, the plate (6) is lifted from its free ends providing to form the fin (4) shape on the surface of the microchannel tube (2). The process of lifting the plates (6) can be performed before or after the assembly operation of the retainer (5) on the microchannel tube (2). Heat transfer areas are formed on the tube (2) after the plates (6) are lifted and the assembly of the fin (4) on the microchannel tube (2) is completed. Since the arms (9) completely contact the bottom and the top of the microchannel tube (2) surface and by means of the plates (6) connected thereto, the heat transfer surface area of the heat exchanger (1) is increased. Consequently, both the entire surface of the microchannel tube (2) is clasped and also the heat transfer surface area is easily formed.
In an embodiment of the present invention, the fin (4) comprises the plate (6) which is lifted to be vertical to the tube (2) surface (Figure 3).
In another embodiment of the present invention, the fin (4) comprises the plate (6) which is lifted to be inclined to the tube (2) surface (Figure 4).
In another embodiment of the present invention, the heat exchanger (1) comprises a housing (8) that remains between the bend (7) and the side of the tube (2). In this embodiment, the defrost heater utilized in no-frost refrigerators and used to melt the frost, which is accumulated on the heat exchanger (1), by heating, can be mounted to the heat exchanger (1) by being passed through this housing (8). Furthermore, increase in defrost effectiveness and decrease in energy consumption by reducing defrost duration are provided.
In an embodiment of the present invention, the heat exchanger (1) is an evaporator.
In another embodiment of the present invention, the heat exchanger (1) is a condenser.
In another embodiment of the present invention, the heat exchanger (1) is used in refrigerators.
The manufacturing method of the heat exchanger (1) of the present invention comprises the following steps:

securing two rectangular shaped sheets to one another at their middle portions,
mounting the two sheets, secured to each other, to the microchannel tube (2) by bending their middle portions such that they will surround the top, bottom and one side of the microchannel tube (2), and
forming by lifting the outer sheet from its ends such that there will be an angle between the microchannel tube (2) surface and themselves while the inner sheet clasps the microchannel tube (2).

It is to be understood that the present invention is not limited to the embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These different embodiments should also be considered within the scope of the claims of the present invention, too.

Claims

A heat exchanger (1) comprising a microchannel tube (2) that has channels (3) arranged in order and parallel to each other, through which refrigerant can pass, and
- a retainer (5) which is formed by bending a rectangular shaped sheet at its center and mounted on the tube (2) such that it will surround the top, bottom and one side of the tube (2),
characterized by

- a fin (4) that has a plate (6) which is formed by another rectangular shaped sheet, secured to the retainer (5) at the center, being bent from the middle over the retainer (5) such that it will surround the retainer (5), and which forms a protrusion on the tube (2) surface by lifting at least one end such that there will be an angle between the tube (2) surface and itself.
A heat exchanger (1) as in Claim 1, characterized by the fin (4) that is configured as pincers.
A heat exchanger (1) as in Claim 1, characterizedby the retainer (5) and the plate (6) that are manufactured from aluminum material.
A heat exchanger (1) as in Claim 1, characterizedby the plate (6) that is manufactured from the sheet, with the length equal to the length of the sheet from which the retainer (5) is manufactured.
A heat exchanger (1) as in Claim 1, characterizedby the retainer (5) which comprises two arms (9) that contact the top and bottom of the tube (2) and a bend (7) that joins these two arms (9).
A heat exchanger (1) as in Claim 5, characterizedby a housing (8) that remains between the bend (7) and the side of the tube (2).
A heat exchanger (1) as in Claim 5, characterizedby the plate (6) with free ends that is secured from its middle portion onto the bend (7) and bent such that it will surround the arms (9).
A heat exchanger (1) as in any one of the above claims, characterized by the plate (6) which is lifted to be vertical to the surface of the tube (2).
A heat exchanger (1) as in any one of the Claims 1 to 7, characterized by the plate (6) which is lifted to be inclined to the surface of the tube (2).
A heat exchanger (1) as in any one of the above claims, which is an evaporator.
A heat exchanger (1) as in any one of the Claims 1 to 9, which is a condenser.
A refrigerator which comprises a heat exchanger (1) as in any one of the above claims.
A manufacturing method for a heat exchanger (1) as in any one of the above claims, comprising the steps of securing two rectangular shaped sheets to one another at their middle portions, mounting the two sheets secured to each other onto the microchannel tube (2) by bending their middle portions such that they will surround the top, bottom and one side of the microchannel tube (2) and lifting the outer sheet from its ends such that there will be an angle between the microchannel tube (2) surface and themselves while the inner sheet clasps the microchannel tube (2).