This application claims the benefit of Korean Patent Application No. 2007-109503 filed in the Korean Intellectual Property Office on Oct. 30, 2007, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
Aspects of the present invention relate to a fuel cell system, and more particularly, to an evaporator for a fuel cell system that generates steam used for a steam reforming reaction.
2. Description of the Related Art
Fuel cells form an electricity generating system to generate electrical energy using a hydrocarbon group fuel. Such fuel cells are classified into polymer electrolyte membrane fuel cells and direct oxidation membrane fuel cells. The direct oxidation membrane fuel cell is generally referred to as a direct methanol fuel cell (DMFC).
The polymer electrolyte membrane fuel cell has superior output characteristics, a low operating temperature, and fast starting and response characteristics. The polymer electrolyte membrane fuel cell has been widely used as a portable power source for vehicles, a distributed power source for houses and public buildings, and a mini power source for electronic devices.
A fuel cell system employing the polymer electrolyte membrane fuel cell includes a fuel cell main body, a fuel reformer, a fuel supplier, and an oxidizing agent supplier. The fuel supplier includes a fuel tank and a fuel pump, and the fuel supplier supplies a fuel to the fuel reformer. The fuel reformer generates hydrogen gas by reforming the fuel and supplies the hydrogen gas to the fuel cell main body. The fuel cell main body generates electrical energy by inducing an electrochemical reaction between the hydrogen gas from the fuel reformer and the oxidizing agent gas.
The fuel reformer may include various constituent elements according to a fuel reforming scheme. For a steam reforming reaction, the fuel reformer may include a heat source, a reforming reaction part, and an evaporator. The heat source generates heat, and the reforming reaction part reforms a fuel using the heat energy. The evaporator heats water and generates steam to provide steam to the reforming reaction part used for the steam reforming reaction.
The evaporator of the fuel cell system generally has a tubular shape or a plate shape. However, in the tubular-shaped evaporator, as a cross-sectional flow area is large, an increase of a contact area between water and the evaporator is not proportional to an increase of an amount of flow. That is, the increment of the contact area is smaller than the increment of the amount of flow. Therefore, the evaporator of the tubular shape has a drawback of low heat transfer efficiency. Meanwhile, if the plate-shaped evaporator has a large area to increase a contact area between water and the evaporator, the entire area of the evaporator increases. Accordingly, the fuel cell system cannot be downsized because of the evaporator.
Aspects of the present invention provide an evaporator for a fuel cell system that improves heat transfer efficiency by increasing a contact area between water and an evaporator while reducing a size thereof.
Aspects of the present invention provide an evaporator including a body having a hollow inner space through which a fluid flows, and a plurality of cell barrier members to divide the hollow inner space into a plurality of spaces, the cell barrier members conducting heat between the plurality of spaces. According to aspects of the present invention, the spaces include at least one first space through which a flue gas flows, and at least one second space through which water flows. According to aspects of the present invention, the spaces may be arranged in a plurality of rows and a plurality of columns. According to aspects of the present invention, the cell barrier members may divide a cross-section of the inner space in a lattice shape.
According to aspects of the present invention, the at least one first space may be adjacent to the at least one second space.
According to aspects of the present invention, the at least one first space may include a plurality of first spaces and the at least one second space may include a plurality of second spaces. According to aspects of the present invention, the first spaces and the second spaces may be alternately arranged in a first direction when viewed in the cross-section of the inner space of the body. According to aspects of the present invention, the first spaces and the second spaces may be alternately arranged in a second direction which crosses the first direction when viewed in the cross-section of the inner space of the body.
According to aspects of the present invention, the flue gas may be supplied to the first spaces from a heat source of a reformer that generates heat in the reformer.
According to aspects of the present invention, the first spaces may be adjacently arranged in the second direction crossing the first direction when viewed in the cross-section of the inner space of the body. According to aspects of the present invention, the second spaces may be adjacently arranged in the second direction when viewed in the cross-section of the inner space of the body.
According to aspects of the present invention, the cell barrier members may include first cell barrier members formed in the second direction and spaced from each other in the first direction, and second cell barrier members formed in the first direction and spaced from each other in the second direction.
According to aspects of the present invention, the second cell barrier members may include at least one through-hole formed in a portion of the second cell barrier members that separate the second spaces. According to aspects of the present invention, each of the at least one through-hole may protrude from a surface of the second cell barrier member.
According to aspects of the present invention, the first spaces and the second spaces may be divided by the first cell barrier members and be alternately arranged in the first direction when viewed in a cross-section of the inner space of the body. According to aspects of the present invention, the second spaces may be divided by the second cell barrier members and be arranged one after another in the second direction when viewed in the cross-section of the inner space of the body.
According to aspects of the present invention, the cell barrier members may divide a cross-section of the inner space in a honeycomb structure. According to aspects of the present invention, the first spaces are adjacent to the second spaces. According to aspects of the present invention, the at least one first space and the at least one second space may have cross-sections of hexagonal shapes of the same size.
According to aspects of the present invention, the first spaces and the second spaces may form a first row in the first direction when viewed in a cross-section of the inner space of the body. According to aspects of the present invention, the first spaces and the second spaces may be alternately arranged in the first row.
According to aspects of the present invention, the first spaces and the second spaces may form a second row in the first direction, and the second row may be adjacent to the first row in the second direction. According to aspects of the present invention, the first spaces and the second spaces may be alternately arranged in the second row. According to aspects of the present invention, a first imaginary line may be spaced from a second imaginary line in the first direction. According to aspects of the present invention, the first imaginary line may pass through a center of one of the first spaces of the first row and be formed along the second direction. According to aspects of the present invention, the second imaginary line may pass through a center of one of the second spaces of the second row and be formed along the second direction.
If steam of the same amount is generated by evaporating water of the same amount, the evaporator according to an exemplary embodiment of the present invention has an overall volume that is smaller than the evaporator according to the related art. Thus, in an exemplary embodiment of the present invention, the size of the evaporator can be reduced compared with the related art.
According to the exemplary embodiments of the present invention, a contact area between water and the evaporator can be increased even though they have the same volumes. Thus, more water can be heated compared with the related art.
Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the aspects of the present invention by referring to the figures.
A fuel supplier 20 includes a fuel tank to store a fuel and a pump to supply the fuel. The fuel supplier 20 supplies the fuel to a fuel reformer 100.
The fuel reforming apparatus 100 receives the fuel from the fuel supplier 20, induces a reforming reaction in the fuel, and generates from the fuel a reformed gas containing hydrogen. The fuel reformer 100 will be described more fully.
An oxidizing agent supplier 30 supplies an oxidizing agent gas to the fuel cell main body 10. The oxidizing agent supplier 30 may supply the air in the atmosphere to the fuel cell main body 10 as an oxidizing agent gas using an air pump.
The reforming reaction part 110 facilitates a reforming reaction of a fuel and generates from the fuel a reformed gas containing hydrogen through the reforming reaction of the fuel by using heat energy. The heat source 120 generates heat energy by a combustion reaction induced when a fuel and air are supplied to the heat source 120. The heat source 120 is located adjacent to the reforming reaction part 110, and provides the heat energy to the reforming reaction part 110. The evaporator 130 heats water and generates steam to provide steam used for the steam reforming reaction through a structure described below.
The evaporator 130 has a cylindrical body 133. The cylindrical body 133 has a generally hollow inner space, and, for example, a fluid flows along a length direction of the cylindrical body 133 in the inner space of the cylindrical body 133. Cell barrier members 134 and 135 divide the cross-section of the inner space of the cylindrical body 133 into a lattice shape. Thus, the inner space of the cylindrical body 133 is divided into a plurality of spaces having a plurality of rows and columns. The spaces, divided by the cell barrier members 134 and 135, include the at least one first space 131 to allow a flow of a flue gas and the at least one second space 132 to allow a flow of water. In this embodiment, a plurality of first and second spaces 131 and 132 are included as an example.
The first spaces 131 are adjacent to the second spaces 132. Heat exchange between the flue gas and the water respectively flowing in the first and second spaces 131 and 132 occurs through the cell barrier members 134 and 135. The cell barrier members 134 and 135 may be made of a material having high heat conductivity.
In this embodiment, the cell barrier members 134 and 135 include first cell barrier members 134 and second cell barrier members 135. The first cell barrier members 134 are spaced from each other in a first direction (x axis direction in
The first spaces 131 and the second spaces 132 are alternately arranged in the first direction when viewed in the cross-section of the inner space of the body 133. The first spaces 131 and the second spaces 132 are alternately arranged in the second direction when viewed in the cross-section of the inner space of the body 133. Since the second spaces 132 are surrounded by the first spaces 131 because of the above structure, a heat exchange area of the embodiment can be increased, compared with the tubular shaped or plate-shaped evaporator according to the related art.
A high temperature flue gas that is discharged after a combustion reaction generated in the fuel cell system is supplied to the first spaces 131. The flue gas used may be supplied from the heat source 120 disposed to adjoin to the evaporator 130 for a structural advantage, as shown in
The first spaces 151 and the second spaces 152 are alternately arranged in a first direction (x axis direction in
Cell barrier members 154 and 155 that divide the inner space of the cylindrical body 153 into the first and second spaces 151 and 152 include first cell barrier members 154 and second cell barrier members 155. The first cell barrier members 154 are spaced from each other in the first direction and are formed in the second direction, and the second cell barrier members 155 are spaced from each other in the second direction and are formed in the first direction. The second cell barrier members 155 are provided with the at least one through-hole 156. The at least one through-hole 156 may include a plurality of through-holes 156. Further, only the second cell barrier members 155 that separate the second spaces 152 are provided with the at least one through-hole 156, but aspects of the present invention are not limited thereto.
Since heat is transferred from the flue gas flowing in the first spaces 151 to the second cell barrier members 155 in the evaporator 150, a heat transfer area is larger than that of the evaporator according to the related art. In addition, according to the evaporator 150 of
The through-hole 156 may be formed by punching. The cell barrier members 154 and 155 of the evaporator 150 may be formed of a metal monolith using a punched sheet. Also, the cell barrier members 154 and 155 are formed of a metal material to have high heat conductivity. A flue gas provided from a heat source flows into the first spaces 151.
As shown in
In the evaporator 160, the second cell barrier members 165 are provided with through-holes 166, as in the evaporator 150 of
The evaporator 170 has a cylindrical body 173. The body 173 has a hollow inner space of, and a fluid flows in the hollow inner space along a length direction thereof, as an example. Cell barrier members 174 divide a cross-section of the inner space into the honeycomb structure. The inner space is divided into a plurality of spaces having a plurality of rows and layers. The spaces divided by the cell barrier members 174 include the first spaces 171 that allow a flow of a flue gas, and the second spaces 172 that allow a flow of water.
In the embodiment, a plurality of rows formed of the first spaces 171 and the second spaces 172 are stacked in a second direction (y axis direction in
That is, as shown in
Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.
Number | Date | Country | Kind |
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10-2007-0109503 | Oct 2007 | KR | national |