US20080251234A1

US20080251234A1 - Regenerator wheel apparatus

Info

Publication number: US20080251234A1
Application number: US11/735,835
Authority: US
Inventors: David Gordon Wilson; Jon M. Ballou; Kelly Ward
Original assignee: Wilson Solarpower Corp
Current assignee: Wilson Solarpower Corp
Priority date: 2007-04-16
Filing date: 2007-04-16
Publication date: 2008-10-16
Also published as: CN101688762A; WO2008130811A4; WO2008130811A1; EP2147273A1

Abstract

A regenerator wheel is disclosed. The regenerator wheel includes a framework, a plurality of ports disposed within the framework, with at least one port of the plurality of ports separated from another port by the framework. The regenerator wheel also includes a plurality of matrixes aligned individually with the plurality of ports.

Description

BACKGROUND OF THE INVENTION

This disclosure relates generally to regenerative heat exchangers, and more particularly to a regenerator wheel apparatus.
Regenerative heat exchangers, or regenerators, also known as heat wheels, are used for energy recovery associated with operations involving heating and cooling. One example of heating and cooling for which such regenerators are employed is that of large spaces such as buildings. Regenerators are used in preheating operations in, for example, steam power plants and in gas adsorption processes and mass transfer operations, such as dehumidification, for example. In order to achieve the results desired, regenerators include what has become known as a matrix. The matrix is the portion of the regenerator that does the absorption and transfer of a specific target species, such as heat, etc. Since operating temperatures of regenerators utilized as noted can exceed 650 degrees Celsius, matrixes are often constructed of ceramic materials. Moreover, ceramics generally have a lower thermal conductivity than metals, which is favorable in regenerative heat exchange applications.
Regenerators have traditionally been configured in several ways to transport the matrix between flow streams of high and low species concentration, such as continuous and discontinuous rotation of the matrix in a regenerator wheel, for example. Often, a significant portion of the mass and/or area of the regenerator wheel comprises the matrix. While some regenerators configured with discontinuous rotation of the regenerator wheel, such as described in U.S. RE37,134, the contents of which are herein incorporated by reference in their entirety, use all of the mass and/or area of the matrix to absorb and transfer the specific target species, others do not. One example of a regenerator that does not use all of the mass and/or area of the matrix is one that is indexed to a finite number of species flow streams, such as four for example. In such devices, a significant area of the matrix may not be used for the purpose for which it is configured.
Because of the cost associated with the production of matrixes, non-utilized sections are not desirable. Furthermore, unused sections of matrix material are undesirable because the matrix itself, especially when made of ceramic material, tends to be on the less robust side with respect to structural durability. Other materials which offer effective heat transfer properties for regenerators do not have the needed structural integrity to be used exclusively as the matrix material.

BRIEF DESCRIPTION OF THE INVENTION

An embodiment of the invention includes a regenerator wheel. The regenerator wheel includes a framework, a plurality of ports disposed within the framework, with at least one port of the plurality of ports separated from another port by the framework. The regenerator wheel also includes a plurality of matrixes aligned individually with the plurality of ports.
Another embodiment of the invention includes a regenerator wheel having a plurality of distinct matrixes, each matrix comprising at least one flow passage, and means for supporting the plurality of distinct matrixes.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 is an end view of a regenerator wheel in accordance with an embodiment of the invention,

FIG. 2 is a section view of a regenerator wheel in accordance with an embodiment of the invention;

FIG. 3 is a section view of a regenerator wheel in accordance with an embodiment of the invention;

FIG. 4 is a an end section view of a regenerator wheel framework in accordance with an embodiment of the invention;

FIG. 5 is a section view of the regenerator wheel framework shown in FIG. 4 in accordance with an embodiment of the invention;

FIG. 6 is a section view of a regenerator wheel framework in accordance with an embodiment of the invention; and

FIG. 7 is an end view of a regenerator wheel framework in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of several embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the figures.
An embodiment of the invention provides a discontinuously rotated or indexed regenerator wheel wherein matrix material is disposed only where useful to transfer the target species, such as at a plurality of ports in a framework. The ports are then alignable with a flow stream of the target species. The ports are appropriately distributed within the regenerator wheel (in one embodiment equally spaced) and their form is based on the shape of the ducts that lead the stream of the target species to and from the matrix. The framework provides enhanced structural integrity and rigidity for the often brittle matrix material. Furthermore, manufacturing costs associated with the matrix representing a significant portion of the mass and/or area of the regenerator wheel can be avoided while maintaining performance of the regenerator. As used herein, the term “regenerator” shall include regenerators used in energy recovery, preheating, exhaust treatment, gas adsorption, and mass transfer applications among others.
Referring now to FIG. 1, a regenerator wheel 50 for use with a discontinuously rotating (or indexing) regenerator is depicted. Evident is that the area of the wheel 50 is made up of both areas not intended for species transfer and ports (where the active matrix resides) that are intended to have utility with respect to species transfer.
The regenerator wheel 50 comprises a framework 55. Framework 55 may be constructed in a number of different ways providing it affords a reliable structure to support and move the matrixes correctly to promote proper operation of the regenerator. Five embodiments are illustrated herein for exemplary purposes but are not to be considered limiting. The first embodiment disclosed is illustrated in FIG. 1 while the second embodiment is illustrated in FIGS. 2 and 3, the third embodiment is illustrated in FIGS. 4 and 5, with the fourth embodiment depicted in FIG. 6 and the fifth embodiment depicted in FIG. 7 In each embodiment, the framework 55 is illustrated as a cylindrical body. Though a cylinder is a convenient shape to work with for a rotary machine, it will be understood that other shapes are also possible without departing from the scope of the invention.
The framework is either of relatively solid construction or constructed of individual components and therefore mostly open. It is to be appreciated that the relatively solid configuration includes foamed material construction (e.g. ceramic foams as marketed by Vesuvius, Belgium). First and second end faces 20 and 22 (best seen with reference to FIG. 2) are presented. These are the faces that interact with fluid flow conduits (not shown) during use of the regenerator. Whereas the use of the face area is a convenient arrangement for a rotary regenerator, departing from this scheme and using, for example, the outer and inner surfaces of a tube shaped regenerator wheel are still within the scope of the present invention. At each end face 20, 22 is located a plurality of ports 65 (illustrated as four in FIG. 1). Within each port 65 is securely disposed one of a plurality of matrixes 60, which may in one embodiment comprise ceramic honeycomb structures, each having at least one passage through which fluid flow (and target species transfer) occurs.
Each of the plurality of matrixes 60 is sized for a specific application. In some embodiments of the invention, all of the matrixes 60 in a particular wheel 50 will be of the same outer dimension while in other embodiments, differing dimensions are utilized. In general, there will be at least two matrixes 60 of equivalent size in each size category of a wheel 50 since species transfer requires movement of a matrix from one stream to another (usually swapping one matrix for another). Furthermore, sealing with the two streams is more easily facilitated by matrixes that have a same outside dimension. Ports 65 may be located relative to each other on each end face 20 or 22 in any pattern needed to match the locations of the fluid flow feeds (not shown) and the index of the regenerator wheel 50. In a radial flow regenerator, as mentioned above, the port sections may be located on the inner and outer faces of the tube shaped regenerator wheel.
In one embodiment, the at least one passage in each of the plurality of matrixes 60 is disposed perpendicularly to end faces 20 and 22, although it is possible to dispose such passages angularly with respect to the faces 20, 22 if a particular application calls for such an angle. Moreover, while four ports 65 are illustrated, more or fewer are contemplated.
With respect to matrix material, it is to be appreciated that any type of matrix material may be incorporated in the configurations disclosed herein.
Returning now to the structure of framework 55, it should be noted that it is desirable that the framework 55 be of light weight to reduce inertia thereof, thereby reducing the amount of force required to index the regenerator wheel 50 from one index position to another. This results in a savings of material and construction costs with respect to the robustness of the machine tasked with rotating the wheel 50 and additionally promotes speedier indexing movements. Speedier indexing movements result in smaller losses due to leakage or decay of the absorbed species. Simultaneously, the framework 55 provides appropriate rigidity to ensure accurate registration of the plurality of matrixes 60 disposed within the plurality of ports 65 with the fluid flow feeds (not shown) through repeated movements of the regenerator wheel 50.
Because the framework 55 is required to provide structural support to the plurality of matrixes 60 and does not need to absorb or transport the target species, it can be made from a variety of materials and processes which, relative to matrix 61 materials and manufacturing processes represent, among other advantages, reduced costs. Furthermore, because the framework 55 does not need to absorb or transport the target species, it may, as noted above, be solid, or have any appropriate structural arrangement to provide enhanced structural integrity, support, and durability as compared to a regenerator wheel that includes a large area of unused matrix 61 material.
As depicted in FIG. 1, one embodiment of the framework 55 is a single piece structural support, made of a filler material 62 with the plurality of ports 65 machined, milled, drilled, or otherwise formed therein. Matrix 60 material is then attached therein adhesively, by interference fit, or otherwise. In one embodiment, the filler material 62 of the framework 55 is the same material as the plurality of matrixes 60 (except that a structure of the framework 55 does not necessarily include the flow passages of the matrix 60 material). Accordingly, the plurality of matrixes 60 and the framework 55 of the regenerator wheel 50 have similar thermal response properties, such as a coefficient of thermal expansion, for example. The framework 55, having similar thermal response properties facilitates maintenance of a substantially uniform thermal expansion throughout the regenerator wheel 50 to reduce thermal stress and enhance structural integrity, thereby reducing possible seal leakage, which may be influenced by warpage of the regenerator wheel 50. As used herein, the term “substantially uniform thermal expansion” in one embodiment shall refer to a thermal expansion ratio of the matrix 60 to the framework 55 contemplated to be no greater than about 1.001 and no less than about 0.999. Such uniform thermal expansion enhances the structural integrity of the entire wheel 50 to reduce seal leakage that may result from deflection of the sealing surface, such as the first and second end faces 20, 22 for example. Tuning of the thermal expansion is significant in the case when the matrixes 60 are bonded into the framework 55, as will be described further below, and preferable if the framework 55 is made of side plates, as will also be described further below. The substantially uniform thermal expansion throughout the regenerator wheel 50 also reduces an accumulation of thermal stresses in response to at least one of an application of high temperatures to the regenerator wheel 50 and a difference in temperatures between a high temperature flow stream and a low temperature flow stream.
In order to reduce a significance of the substantially uniform thermal expansion coefficient while maintaining functional suitability of the wheel 50, a layer of flexible binder 69 is disposed between each port 65 of the framework 55 and each matrix 60 to compensate for a thermal expansion differential therebetween. It will be appreciated that material of the layer shall withstand the operating temperatures and be flexible in nature. One example of such material, suitable for temperatures up to 800° F., is “Duraseal 1533”, commercially available from Cotronics Corporation of Brooklyn, N.Y.
The filler material 62 of the framework 55 may not be appropriate for contact with a seal (not specifically shown) of the discontinuously rotating regenerator. Therefore, in embodiments where this is an issue, the regenerator wheel 50 further includes at least one seal face 70 made from a material appropriate for contact with the seal of the discontinuously rotating regenerator. Seal face 70 may be disposed to be coplanar with face 20 or may be simply attached thereto, in the event that the regenerator seal mechanism (not shown) is so configured.
Another exemplary process for assembly of the regenerator wheel 50 includes positioning each of the plurality of matrixes 60 into a mold, in the appropriate port 66 location. The process further includes introducing into the mold the framework 55 filler material 62 through a foaming technique for open cell ceramic foam, thereby providing the regenerator wheel 50 having the plurality of matrixes 60 disposed within the plurality of ports 65 of the framework 55 with a single foamed bonding structure. In a further embodiment, the open cell ceramic foam is machined to receive the matrices 60 at the port sections 65 and an appropriate binder fulfilling the substantially uniform thermal expansion coefficient is applied.
Referring now to FIG. 2 a side section view of another embodiment of the regenerator wheel 50 is depicted. The framework 55 includes a set of side plates 80 that include the plurality of ports 65 in which the plurality of matrixes 60 are disposed. At least one matrix 61 is disposed within a corresponding set of the plurality of ports 65, such as holes within each side plate 81, 82 of the set of side plates 80. Each port 66 includes geometry that is complementary to that of the matrix 61, to accommodate disposal of the matrix 61 within the port 66. One or more spacers 85 may be disposed between the two side plates 81, 82 to provide an appropriate structural integrity and external dimensions of the regenerator wheel 50 for interface with seals of the discontinuously rotating regenerator. The side plates 81, 82 may be integrated with the one or more spacers 85 via at least one of an adhesive bonding, mechanical fasteners, and welding, for example. The matrix 61 is retained within the port 66 by a ceramic binder or another appropriate binding material for the chosen material combination of the matrix 61 and the side plates 81, 82. In an exemplary embodiment, at least one of the side plates 81, 82 and the ceramic binder is the same material as the matrix 61, to provide substantially uniform thermal expansion, as described above. In one embodiment the matrixes 61 in each port are of a size greater than the flow passage. The additional matrix material serves as insulation to prevent thermal losses to the environment.
Referring now to FIG. 3, another embodiment of the regenerator wheel 50 is depicted. The side plates 81, 82 include a set of axial retention features 90, such as a step within the side plates 81, 82 to retain the matrix 61 within the port 66. The matrix 61 includes a corresponding set of axial retention features 91, such as a step included on the matrix 61, for example. Accordingly, the matrix 61 can be retained within the side plates 81, 82 absent a bonding material, such as the ceramic binder. In an exemplary embodiment, there is a minimal clearance between the port 66 and the matrix 61, thereby allowing the matrix 61 to be a floating matrix 61, or free to translate in an axial direction within limits established by the axial retention features 90, 91, such as along a centerline 95 within the set of side plates 80, for example.
Referring now to FIGS. 4 and 5, section views of another embodiment are depicted. The framework 55 includes the two side plates 81, 82, a non-permeable circumferential plate 96 (also herein referred to as a “boundary plate”), and rigid, non-permeable segmentation plates 97 (also herein referred to as “separator plates”) which are interconnected in a hub 98. The circumferential plate 96 defines an outer boundary of the wheel 50 and is disposed between outer edges of the set of side plates 81, 82, thereby defining an open space between the side plates 81, 82 and within the circumferential plate 96. The segmentation plates 97 are disposed within the open space and create separated segments 99 that define the ports 65 into which the matrix material can be disposed.
In one embodiment, the side plates 81, 82 are made of a ceramic honeycomb including axial passages that allow flow of the target species, and segmentation plates 97 are solid ceramic, to prevent flow of the target species between the separated segments 99. In another embodiment the matrix material used to fill segments 99 is one of the ceramic foam (aforementioned) and a cloth-like heat transfer material. One example of the cloth-like heat transfer material is “Nextel 312”, commercially available from TMO Thermostatic Industries, Inc. of Huntington Park, Calif. The matrix material (disposed within segments 99) can be rigidized and/or bonded to at least one of the segmentation plates 97 and the circumferential plate 96 by commonly used methods.
Segmentation plates 97 prevent flow in a circumferential direction between segments 99 thereby allowing use of at least one of the cloth-like and foamed matrix structure, which do not have strictly axial passages. This latter arrangement will potentially lower the weight of the ceramic matrix significantly for continuously and discontinuously rotated regenerators. In one embodiment, the segmentation plates 97 are a one piece, unitized structure. While a shape of the segments 99 has been depicted as pie shaped, it will be appreciated that the scope of the invention is not so limited to these shapes and the invention will also apply to regenerator apparatuses having other shapes, such as round segments, for example.
FIG. 6 depicts another embodiment in which the side plate 81, circumferential plate 96, segmentation plates 97, and hub 98 are machined out of a ceramic honeycomb cylinder which might itself comprise an assembly of several bonded blocks of extrusions, thereby providing a unitized framework 55 structure. The hub 98 is an interconnection of segmentation plates 97.
In another embodiment, as depicted in FIG. 7, the framework 55 includes a unitized circumferential plate 96, segmentation plates 97, and the hub 98, (absent the side plates 81, 82) to form an open framework 55. The hub 98 can fill a volume or have a mass of its own, at the center of the framework 55. Segments 99 are filled with ceramic cloth which is rigidized and then cut off at the front and back by an appropriate means, such as a saw or laser for example, thereby eliminating a need for side plates 81, 82. At least a portion of the front and the back of the ceramic cloth shall be rigidized to provide appropriate structural rigidity to interface with the flow feeds, however a full depth, through the thickness of the ceramic cloth, need not be rigidized.
While an embodiment has been described as rotatably disposed about a center, it will be appreciated that the scope of the invention is not so limited, and that the invention will also apply to regenerator apparatuses that transport the matrix from one fluid flow stream to another via alternate motion, such as linear or curve linear translation, for example.
While an embodiment has been depicted having four distinct ports 65, it will be appreciated that the scope of the invention is not so limited, and that the invention will also apply to regenerator wheels 50 having other numbers of distinct ports 65, such as two, three, five, or more, for example. While an embodiment has been described having steps as axial retention features, it will be appreciated that the scope of the invention is not so limited, and that the invention will also apply to regenerator wheels 50 that may have other axial retention features, such as a groove with snap rings, for example to retain the port 66 within the side plates 80 of the carrier 55.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

Claims

1. A regenerator wheel comprising:

a framework, a plurality of ports disposed within the framework, at least one port of the plurality of ports separated from another port by the framework; and

a plurality of matrixes aligned individually with the plurality of ports.

2. The wheel as claimed in claim 1, wherein:

at least one matrix of the plurality of matrixes comprises at least one straight flow passage.

3. The wheel as claimed in claim 2, wherein:

at least one matrix comprises a honeycomb configuration.

4. The wheel as claimed in claim 1, wherein:

at least one matrix of the plurality of matrixes is embedded within the framework.

5. The wheel as claimed in claim 4, wherein:

the framework and the at least one matrix are the same material.

6. The wheel as claimed in claim 5, wherein:

the framework and the at least one matrix are ceramic.

7. The wheel as claimed in claim 1, wherein:

at least one matrix of the plurality of matrixes comprises extruded ceramic honeycomb.

8. The wheel as claimed in claim 1, wherein:

the framework comprises a single piece structure.

9. The wheel as claimed in claim 8 wherein the single piece structure is a foamed structure.

10. The wheel as claimed in claim 1, wherein:

the framework comprises a set of side plates, each side plate comprising the plurality of ports; and

at least one matrix of the plurality of matrixes is disposed within a corresponding set of the plurality of ports.

11. The wheel as claimed in claim 10, wherein the framework further comprises:

at least one spacer disposed between two side plates of the set of side plates.

12. The wheel as claimed in claim 10, further comprising:

a ceramic binder between at least one matrix and the corresponding set of the plurality of ports.

13. The wheel as claimed in claim 12, wherein:

at least one of the set of side plates and the ceramic binder comprise the same material as the at least one matrix.

14. The wheel as claimed in claim 10, wherein:

at least one of the framework and the at least one matrix comprise a set of axial retention features.

15. The wheel as claimed in claim 14, wherein:

the at least one matrix is a floating matrix within the set of axial retention features.

16. The wheel as claimed in claim 1, further comprising:

a flexible binder disposed between each port of the plurality of ports and each corresponding matrix of the plurality of matrixes.

17. The wheel as claimed in claim 1, wherein the framework comprises:

a set of side plates, each side plate having at least one straight flow passage corresponding to each port of the plurality of ports;

a boundary plate disposed between outer edges of the set of side plates, thereby defining a space between the set of side plates and an outer boundary of the wheel; and

at least one separator plate disposed within the space between the set of side plates, thereby defining the plurality of ports.

18. The wheel as claimed in claim 17, wherein:

the plurality of matrixes comprise a cloth-like material.

19. The wheel as claimed in claim 17, wherein:

the at least one separator plate is a unitized structure.

20. The wheel as claimed in claim 17, wherein:

one side plate of the set of side plates, the boundary plate, and the at least one separator plates are a unitized structure.

21. The wheel as claimed in claim 1 wherein the framework comprises:

a boundary plate defining an outer boundary of the wheel, the boundary plate defining an open space; and

at least one separator plate disposed within the open space of the boundary plate, thereby defining a plurality of open ports.

22. The wheel as claimed in claim 21 wherein:

the matrix comprises a rigid filler material.

23. The wheel as claimed in claim 21 wherein:

the matrix comprises a rigidized ceramic cloth material disposed within the plurality of open ports.

24. A regenerator wheel comprising:

a plurality of distinct matrixes, each matrix comprising at least one flow passage; and

means for supporting the plurality of distinct matrixes.

25. The wheel as claimed in claim 24, further comprising:

a flexible binder disposed between the plurality of distinct matrixes and the means for supporting.

26. The wheel as claimed in claim 24, wherein:

the plurality of distinct matrixes and the means for supporting comprise the same material.

27. The wheel as claimed in claim 26, wherein:

the means for supporting comprises a framework of filler material.

28. The wheel as claimed in claim 24, wherein:

the means for supporting comprises a set of side plates.