U.S. patent application number 10/608809 was filed with the patent office on 2004-06-24 for plate-type heat exchanger.
Invention is credited to Dobbs, Gregory M., Freihaut, James D..
Application Number | 20040118554 10/608809 |
Document ID | / |
Family ID | 26855121 |
Filed Date | 2004-06-24 |
United States Patent
Application |
20040118554 |
Kind Code |
A1 |
Dobbs, Gregory M. ; et
al. |
June 24, 2004 |
Plate-type heat exchanger
Abstract
Existing plate-type heat exchangers typically include plates
that are constructed of metal or paper, which are only capable of
transferring a limited amount of moisture, if any, from one side of
the plate to the other side. The present invention is a plate-type
heat exchanger wherein the plates are constructed of ionomer
membranes, such as sulfonated or carboxylated polymer membranes,
which are capable of transferring a significant amount of moisture
from one side of the membrane to the other side. Incorporating such
ionomer membranes into a plate-type heat exchanger provides the
heat exchanger with the ability to transfer a large percentage of
the available latent heat in one air stream to the other air
streams. The ionomer membrane plates are, therefore, more efficient
at transferring latent heat than plates constructed of metal or
paper.
Inventors: |
Dobbs, Gregory M.;
(Glastonbury, CT) ; Freihaut, James D.; (South
Windsor, CT) |
Correspondence
Address: |
WALL MARJAMA & BILINSKI
101 SOUTH SALINA STREET
SUITE 400
SYRACUSE
NY
13202
US
|
Family ID: |
26855121 |
Appl. No.: |
10/608809 |
Filed: |
June 27, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10608809 |
Jun 27, 2003 |
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10160370 |
May 31, 2002 |
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6684943 |
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10160370 |
May 31, 2002 |
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09470165 |
Dec 22, 1999 |
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60158533 |
Oct 8, 1999 |
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Current U.S.
Class: |
165/166 ;
165/905 |
Current CPC
Class: |
F28D 9/0062 20130101;
F28D 21/0015 20130101; F28D 9/0037 20130101; F24F 3/147 20130101;
F24F 2003/1435 20130101; Y10S 165/905 20130101 |
Class at
Publication: |
165/166 ;
165/905 |
International
Class: |
F28F 003/00 |
Claims
What is claimed is:
1. A plate-type heat exchanger, comprising: (a) a plurality of
parallel plates spaced apart from one another thereby forming
alternating first and second passageways for a first gas stream and
a second gas stream to pass therethrough, respectively, said plates
comprising an ionomer membrane having four sides; (b) means for
spacing apart said parallel plates from one another; (c) means for
sealing two opposing sides of said first passageways thereby
allowing the first gas stream to pass therethrough in a first
direction; and (d) means for sealing two opposing sides of said
second passageways thereby allowing the second gas stream to pass
therethrough in a second direction.
2. The plate-type heat exchanger of claim 1 wherein said ionomer
membrane is a sulfonated polymer membrane.
3. The plate-type heat exchanger of claim 2 wherein said sulfonated
polymer membrane comprises a perfluoronated backbone chemical
structure.
4. The plate-type heat exchanger of claim 2 wherein said sulfonated
polymer membrane comprises a hydrocarbon backbone chemical
structure.
5. The plate-type heat exchanger of claim 1 wherein said ionomer
membrane is a carboxylated polymer membrane.
6. The plate-type heat exchanger of claim 1 wherein said spacing
apart means and said sealing means for said first passageway are
the same.
7. The plate-type heat exchanger of claim 6 wherein said spacing
apart means and said sealing means for said first passageway is a
continuous corrugated sheet interposed between said parallel plates
that form said first passageway.
8. The plate-type heat exchanger of claim 1 wherein said spacing
apart means and said sealing means for said second passageway are
the same.
9. The plate-type heat exchanger of claim 8 wherein said spacing
apart means and said sealing means for said second passageway is a
continuous corrugated sheet interposed between said parallel plates
that form said second passageway.
10. The plate-type heat exchanger of claim 1 wherein said scaling
means for said first passageways comprise two spacer bars affixed
to opposing sides of said parallel plates that form said first
passageway.
11. The plate-type heat exchanger of claim 1 wherein said sealing
means for said second passageways comprise two spacer bars affixed
to opposing sides of said parallel plates that form said second
passageway.
12. The plate-type heat exchanger of claim 11 wherein said sealing
means for said first passageways comprise two additional spacer
bars affixed to opposing sides of said parallel plates that forms
said first passageways, wherein said additional spacer bars for
sealing said first passageways are perpendicular to said spacer
bars for sealing said second passageways.
13. The plate-type heat exchanger of claim 11 wherein said sealing
means for said first passageways comprise two additional spacer
bars affixed to opposing sides of said parallel plates that form
said first passageways, wherein said additional spacer bars for
sealing said first passageways are parallel to said spacer bars for
sealing said second passageways.
14. The plate-type heat exchanger of claim 1 wherein said sealing
means for said first passageways comprises creating flanges on
opposing sides of said parallel plates that overlap and form said
first passageway.
15. The plate-type heat exchanger of claim 1 wherein said sealing
means for said second passageways comprises creating flanges on
opposing sides of said parallel plates that overlap and form said
second passageway.
16. The plate-type heat exchanger of claim 1 wherein said spacing
apart means comprises two spacer bars affixed to opposing sides of
said parallel plates.
17. The plate-type heat exchanger of claim 1 wherein said spacing
apart means comprises a corrugated lattice structural sheet.
18. The plate-type heat exchanger of claim 1 wherein said parallel
plates further comprise a webbed sheet adjacent said ionomer
membranes.
19. The plate-type heat exchanger of claim 1 wherein said parallel
plates further comprise said ionomer membranes interposed between
two webbed sheet.
20. The plate-type heat exchanger of claim 1 wherein said parallel
plates further comprise a webbed sheet embedded within said ionomer
membranes.
21. The plate-type heat exchanger of claim 1 wherein said parallel
plates further comprise a sheet of polytetrafluroethylene adjacent
one side of said ionomer membranes.
22. The plate-type heat exchanger of claim 21 wherein said parallel
plates further comprise an other sheet of polytetrafluroehtylene
adjacent an other side of said ionomer membranes.
23. A plate-type heat exchanger, comprising: (a) a plurality of
parallel ionomer membranes spaced apart from one another thereby
forming alternating first and second passageways for a first gas
stream and a second gas stream to pass therethrough, respectively,
each of said ionomer membranes having four sides; (b) means for
spacing apart said parallel ionomer membranes from one another; (c)
means for sealing two opposing sides of said first passageways
thereby allowing the first gas stream to pass therethrough in a
first direction; and (d) means for sealing two opposing sides of
said first passageways thereby allowing the second gas stream to
pass therethrough in a second direction.
24. The plate-type heat exchanger of claim 23 wherein said ionomer
membrane is a sulfonated polymer membrane.
25. The plate-type heat exchanger of claim 23 wherein said ionomer
membrane is a carboxylated polymer membrane.
26. A plate-type heat exchanger, comprising: (a) a plurality of
parallel plates spaced apart from one another thereby forming
alternating first and second passageways for a first gas stream and
a second gas stream to pass therethrough, respectively, said plates
comprising an ionomer membrane having four sides; (b) a corrugated
lattice structural sheet interposed between said parallel plates,
thereby spacing apart said parallel plates from one another, (c)
means for sealing two opposing sides of said first passageways
thereby allowing the first gas stream to pass therethrough in a
first direction; and (d) means for sealing two opposing sides of
said second passageways thereby allowing the second gas stream to
pass therethrough in a second direction.
27. The plate-type heat exchanger of claim 26 wherein said plates
further comprise a planar lattice sheet adjacent said ionomer
membrane.
28. The plate-type heat exchanger of claim 26 wherein said
corrugated lattice structural sheet comprises cross members that
intersect at vertices and wherein said planar lattice sheet
comprises segments that intersect at intersection points and
wherein said vertices of said corrugated lattice structural sheet
and said intersection points of said planar lattice plate
align.
29. The plate-type heat exchanger of claim 26 wherein said plates
further comprise two planar lattice sheets adjacent both sides of
said ionomer membrane.
30. The plate-type heat exchanger of claim 29 wherein said
corrugated lattice structural sheet comprises cross members that
intersect at vertices and wherein said planar lattice sheet
comprises segments that intersect at intersection points and
wherein said vertices of said corrugated lattice structural sheet
and said intersection points of said planar lattice plate
align.
31. The plate-type heat exchanger of claim 26 wherein said ionomer
membrane is a sulfonated polymer membrane.
32. The plate-type heat exchanger of claim 26 wherein said ionomer
membrane is a carboxylated polymer membrane.
33. A plate-type heat exchanger, comprising: (a) a plurality of
parallel plates spaced apart from one another thereby forming
alternating first and second passageways for a first gas stream and
a second gas stream to pass therethrough, respectively, said plates
comprising an ionomer membrane having four sides; (b) a layer of
webbed netting interposed between said parallel plates, thereby
spacing apart said parallel plates from one another; (c) means for
sealing two opposing sides of said first passageways thereby
allowing the first gas stream to pass therethrough in a first
direction; and (d) means for sealing two opposing sides of said
first passageways thereby allowing the second gas stream to pass
therethrough in a second direction.
34. The plate-type heat exchanger of claim 33 wherein said webbed
netting comprises nodes having a diameter equal to the height of
the first and second passageway.
35. The plate-type heat exchanger of claim 33 wherein said ionomer
membrane is a sulfonated polymer membrane.
36. The plate-type heat exchanger of claim 33 wherein said ionomer
membrane is a carboxylated polymer membrane.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional
Application No. 60/158,533, filed Oct. 10, 1999. This is also a
continuation application of U.S. Ser. No. 09/470,165, filed Dec.
22, 1999, the entirety of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] This invention relates to a plate-type exchanger and more
particularly, to a plate-type heat exchanger wherein the plates
comprise a polymer membrane having enhanced moisture transfer
properties.
BACKGROUND ART
[0003] Heating, ventilation and air conditioning (HVAC) systems
typically recirculate air, exhaust a portion of the re-circulating
air, and simultaneously replace such exhaust air with fresh air. In
order to maintain an air temperature and humidity level within a
certain space at or near a set point, it is desirable to condition
the fresh air the temperature and humidity level set point.
Unfortunately, the temperature and humidity of fresh air often
differ substantially from those of the set points. For example,
during hot and humid periods, such as the summer months, the
incoming fresh air typically has a higher temperature and/or
humidity level than desired. Additionally, during cold and/or dry
periods, such as the winter months, the incoming fresh air
typically has a lower temperature and humidity level than desired.
The HVAC system must, therefore, condition the fresh air before
introducing it to the room.
[0004] HVAC systems are typically designed according to the worst
climatic conditions for the geographic area in which the HVAC
system will be located. Such worst case climatic conditions are
referred to as a cooling and heating "design day." Conditioning the
fresh air during such extreme climatic conditions creates a
significant load on the HVAC system. System designers, therefore,
typically design the HVAC system with sufficient capacity to
maintain the set point during the design day conditions. In order
to create the required capacity, the HVAC system may include
oversized equipment. Alternatively, as discussed in U.S. Pat. No.
4,051,898, which is hereby incorporated by reference, in order to
reduce the load on the HVAC system, system designers often
incorporate ventilators within the HVAC system. Reducing the
ventilation load on the HVAC system decreases its capacity
requirements, which, in turn, allows the designers to specify
smaller sized equipment, thereby leading to a more efficient
design.
[0005] Referring to FIG. 1, a ventilator 10 typically includes a
plate-type heat exchanger 12 which creates alternating flow
passages for the fresh air stream and exhaust air stream to pass
therethrough. The flow passages are typically either parallel or
perpendicular to one another. This figure illustrates a cross flow
heat exchanger because the alternating flow passages are
perpendicular to one another. Specifically, one air stream enters
the ventilator 10 through opening 11, passes through the plate-type
heat exchanger 12, and exits the ventilator 10 through opening 13,
and the other air stream enters the ventilator 10 through opening
15, passes through the plate-type heat exchanger 12, and exits the
ventilator 10 through opening 17. However, if the alternating flow
passages are parallel to one another and the air streams are in the
same direction, then the heat exchanger is referred to as a co-flow
heat exchanger. Additionally, if the alternating flow passages are
parallel to one another but the air streams directly oppose one
another, then the heat exchanger is referred to as a counterflow
heat exchanger.
[0006] Regardless of the direction of the flow patterns, as the air
streams pass through the passageway and along opposite sides of the
plates, the heat or energy in one air stream is transferred to the
other air stream. Depending upon the material of the plates 20,
they can transfer sensible heat or both sensible and latent heat.
Specifically, if the plates 20 are constructed of a material that
is only capable of transferring sensible heat, then the ventilator
is referred to as a heat recovery ventilator (HRV). If, however,
the plates 20 are constructed of a material that is capable of
transferring latent heat, as well as sensible heat, then the
ventilator is referred to as an energy recovery ventilator (ERV).
For example, metal plates, such as aluminum plates, absorb a
portion of the thermal energy in one air stream and transfer such
energy to the other air stream by undergoing a temperature change
without allowing any moisture to pass therethrough. Therefore, a
ventilator constructed of metal plates is referred to as a HRV.
Although plates 20 constructed of paper typically have a lower
thermal conductivity than metal, paper may be capable of
transferring some sensible heat. These plates, however, are capable
of transferring some latent heat because such materials are capable
of transferring moisture between air streams. A ventilator having
plates constructed of material capable of transferring moisture
between air streams is, therefore, referred to as an ERV.
[0007] It is generally understood that an ERV is more versatile and
beneficial than an HRV. However, materials such as paper limit the
plate's ability to transfer a larger portion of the latent heat
from one air stream to the other air stream. Therefore, it is
desirable to produce an ERV with a plate having a greater latent
heat transfer efficiency. The cost of the more efficient material,
however, cannot disrupt the cost benefit of including an ERV within
a HVAC system. As discussed hereinbefore, utilizing a ventilator to
pre-condition the fresh air is an alternative to increasing the
size of the HVAC system. Specifically, pre-conditioning the fresh
air allows the system designers to utilize a design day having more
moderate parameters, which, in turn, make possible the inclusion of
smaller, less costly equipment. Such equipment will also consume
less energy, thereby making it less expensive to operate. Hence,
including an ERV within a HVAC system is perceived as a low cost
method for increasing the system's overall operating efficiency.
However, if the cost of a more efficient plate material
significantly increases the first cost of the ERV, then including
an ERV within a HVAC system decreases its financial benefit.
Therefore, it is desirable that the plates within the plate-type
heat exchanger be constructed of a low cost material, as well as a
material that has the ability to effectively transfer latent
heat.
[0008] Another alternative to increasing the plate material's
ability to transfer latent heat is to pressurize the ERV because
pressurizing the ERV increases the plate's ability to transfer
latent heat from one air stream to the other by increasing the
water concentration difference across the plate. A typical HVAC
system, however, currently operates at about ambient pressure.
Therefore, pressurizing the HVAC system and more particularly, the
ERV, would require adding additional equipment, such as a
compressor, to the HVAC system. Although pressurizing the ERV would
increase its efficiency, adding the necessary equipment to
pressurize the ERV would increase the HVAC system's overall cost.
Again, including an ERV within a HVAC system is currently perceived
as a low cost method for increasing its overall efficiency because
doing so decreases the size and operating cost of the HVAC system.
Pressurizing the HVAC system, alternatively, would only increase
the size of such system by additional equipment, thereby
eliminating the cost benefit of adding an ERV to an HVAC
system.
[0009] What is needed is a plate-type heat exchanger wherein the
plates are constructed of a cost effective material, other than
paper, that is capable of transferring a larger percentage of the
available latent heat in one air stream to the other air streams,
while maintaining the ERV's ability to operate at about ambient
pressure.
DISCLOSURE OF INVENTION
[0010] The present invention is a plate-type heat exchanger wherein
the plates are ionomer membranes, such as sulfonated or
carboxylated polymer membranes, which are capable of transferring a
significant amount of moisture from one of its side to the other.
Because the ionomer membrane plates are capable of transferring a
significant amount of moisture, the plate-type heat exchanger is
capable of transferring a large percentage of the available latent
heat in one air stream to the other air streams. Therefore, a heat
exchanger having ionomer membrane plates is more efficient than a
heat exchanger constructed of paper plates. Utilizing such a
material not only improves the latent effectiveness factor of the
ERV, but does so without pressuring the HVAC system or adding
additional equipment, thereby improving the cost benefit of
including an ERV within an HVAC system.
[0011] Accordingly the present invention relates to a plate-type
heat exchanger, including a plurality of parallel plates spaced
apart from one another to thereby form alternating first and second
passageways for a first gas stream and a second gas stream to pass
therethrough, respectively, the plates being comprised of a ionomer
membrane having four sides, a means for spacing apart the parallel
plates from one another, a means for sealing two opposing sides of
the first passageways thereby allowing the first gas stream to pass
therethrough in a first direction, and a means for sealing two
opposing sides of the first passageways thereby allowing the second
gas stream to pass therethrough in a second direction.
[0012] In an alternate embodiment of the present invention, the
ionomer membranes may be sulfonated or carboxylated polymer
membranes, which can be produced by sulfonating or carboxylating
hydrocarbon or perfluronated polymers. Therefore, in a further
embodiment of the present invention, the sulfonated or carboxylated
polymer membrane shall comprise a perfluronated backbone chemical
structure. In an even further alternate embodiment of the present
invention, the sulfonated or carboxylated polymer membrane shall
comprise a hydrocarbon backbone chemical structure.
[0013] Both the sulfonated polymer membrane, comprising the
perfluoronated backbone chemical structure, and the sulfonated
polymer membrane, comprising the hydrocarbon chemical structure,
significantly improve the plate-type heat exchanger's ability to
transfer latent heat between air streams in comparison to the
currently available plate-type heat exchangers comprising paper
plates because both types of sulfonated polymer membranes have the
ability to transfer a significantly greater amount of moisture.
Additionally, the sulfonated polymer membrane comprising the
hydrocarbon backbone structure is typically less expensive to
manufacture than a sulfonated polymer membrane comprising a
perfluoronated backbone structure because fluorine chemical
processing is typically more expensive than ordinary hydrocarbon
organic chemistry. Therefore, although there is a cost benefit for
including an ERV having a plate-type heat exchanger constructed of
sulfonated polymer membranes with a perfluoronated backbone
stricture into an HVAC system, utilizing plates constructed of
sulfonated polymer membranes having a hydrocarbon backbone would
further increase the ERV's cost benefit.
[0014] The foregoing features and advantages of the present
invention will become more apparent in light of the following
detailed description of exemplary embodiments thereof as
illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 illustrates a ventilator comprising a prior art
plate-type heat exchanger having a plurality of alternating counter
flow passageways therein.
[0016] FIG. 2 illustrates a plurality of ionomer membrane plates
for constructing a plate-type heat exchanger.
[0017] FIG. 3 illustrates the plurality of ionomer membrane plates
illustrated in FIG. 2 along with spacer bars located along two
sides of each plate for spacing apart the plates and sealing the
passageways therebetween.
[0018] FIG. 4 illustrates an alternate means for sealing the
passageways by creating flanges on opposing sides of the ionomer
membrane plates.
[0019] FIG. 5 is a plate-type heat exchanger of the present
invention constructed of parallel spaced ionomer membrane
plates.
[0020] FIG. 6 is an alternate embodiment of the plate-type heat
exchanger of the present invention further comprising continuous
corrugated sheets interposed between the ionomer membrane
plates.
[0021] FIG. 7 is an alternate embodiment of the plate-type heat
exchanger of the present invention wherein corrugated lattice
structural sheets are interposed between the ionomer membrane
plates to create the alternating passageways.
[0022] FIG. 8 is a sheet of a lattice structure.
[0023] FIG. 8A is an enlargement of a portion of the corrugated
lattice structure sheet in FIG. 8.
[0024] FIG. 9 is a cross section of the plate-type heat exchanger
illustrated in FIG. 7, taken along line 9-9.
[0025] FIG. 10 is a cross section of the plate-type heat exchanger
illustrated in FIG. 7, taken along line 10-10.
[0026] FIG. 11 is a side view of a ionomer membrane plate
interposed between two planar lattice sheets.
[0027] FIG. 12 depicts a planar lattice sheet.
[0028] FIG. 13 illustrates a corrugated lattice structural sheet
interposed between two planar lattice sheets, wherein the ionomer
membrane plates are adjacent the opposite sides of the planar
lattice sheets.
[0029] FIG. 14 is an alternate embodiment of the plate-type heat
exchanger of the present invention comprising webbed sheets
adjacent to the ionomer membrane plates.
[0030] FIG. 15 is a cross section of the plate-type heat exchanger
illustrated in FIG. 14, taken along line 15-15.
[0031] FIG. 16 is a cross section of the plate-type heat exchanger
illustrated in FIG. 15, taken along line 16-16.
[0032] FIG. 17 is a cross section of the plate-type heat exchanger
illustrated in FIG. 15, taken along line 17-17.
[0033] FIG. 18 is an alternate embodiment of the webbed supported
ionomer membrane plate wherein one webbed sheet is adjacent the
ionomer membrane plate.
[0034] FIG. 19 is a further embodiment of the webbed supported
ionomer membrane plate wherein the webbed sheet is embedded within
the ionomer membrane plate.
[0035] FIG. 20 is an ionomer membrane interposed between two layers
of polytetrafluroehtylene.
[0036] FIG. 21 is an ionomer membrane adjacent one layer of
polytetrafluroehtylene.
[0037] FIG. 22 is an alternate embodiment of the plate-type heat
exchanger of the present invention wherein webbed sheets are
interposed between the ionomer membrane plates to create the
alternating passageways.
[0038] FIG. 23 is a cross section of the plate-type heat exchanger
illustrated in FIG. 22, taken along line 23-23.
[0039] FIG. 24 is a cross section of the plate-type heat exchanger
illustrated in FIG. 22, taken along line 24-24.
BEST MODE FOR CARRYING OUT THE INVENTION
[0040] Referring to FIG. 2, there is shown a plurality of plates 20
spaced apart from one another to form passageways (i.e., gaps or
spaces) between the plates 20. The plates 20 are constructed of an
ionomer membrane, which has a high moisture transfer
characteristic. An ionomer membrane shall mean a membrane composed
of an ion containing polymer, such as a sulfonated polymer membrane
or a carboxylated polymer membrane that is capable of transferring
moisture from one of its sides to the other. A sulfonated polymer
membrane shall mean a layer of polymer comprising a sulfonated ion
(SO.sub.3.sup.-/+) within its chemical structure. The sulfonated
ion (SO.sub.3.sup.-/+) is typically located within the side chain
of a polymer having a perfluoronated or hydrocarbon backbone
structure. Examples of a generic chemical structure for a
sulfonated polymer membrane comprising a perfluoronated backbone
chemical structure includes the following: 1
[0041] wherein, m and n are comparable variables;
[0042] and 2
[0043] Moreover, examples of commercially available sulfonated
polymer membranes having a perfluoronated chemical structure
include those membranes manufactured by W. L. Gore &
Associates, Inc., of Elkton, Md. and distributed under the
tradename GORE-SELECT and those perfluoronated membranes
manufactured by E. I. du Pont de Nemours and Company and
distributed under the tradename NAFION.
[0044] An example of a generic chemical structure for a sulfonated
polymer membrane comprising a hydrocarbon backbone chemical
structure includes the following: 3
[0045] wherein, m and n are comparable variables;
[0046] and 4
[0047] Moreover, an example of a commercially available sulfonated
polymer membrane having a hydrocarbon backbone chemical structure
includes the polymer membrane manufactured by the Dais Corporation,
of Odessa, Fla., and distributed under the product name DAIS 585.
The cost of sulfonated polymer membranes comprising a hydrocarbon
backbone chemical structure is currently about one percent (1%) to
ten percent (10%) of the cost of sulfonated polymer membranes
comprising a perfluoronated backbone chemical structure. Therefore,
it is especially preferable for the plates 20 of a plate-type heat
exchanger to be constructed of sulfonated polymer membranes
comprising a hydrocarbon backbone chemical structure because
incorporating such plates into an ERV improves its latent
effectiveness factor while minimizing its cost.
[0048] The sulfonated polymer membranes do not necessarily require
a hydrocarbon or perfluoronated backbone chemical structure.
Rather, the backbone could be a block or random copolymer. The
desirable thickness of the sulfonated polymer membranes is
dependent upon the their physical properties, which are controlled
by the chemical backbone structure, length of side chains, degree
of sulfonation, and ionomic form (i.e., acid, salt, etc.). However,
such block or random copolymer must have the ionic sulfonate group
(SO.sub.3). Additionally, the polymer membrane may be fully or
partially sulfonated. Altering the degree of sulfonation affects
the polymer membrane's ability to transfer moisture, and it is
generally preferable to have a high degree of sulfonation within
the polymer membrane.
[0049] It may also be preferable to utilize a carboxylate polymer
membrane in lieu of a sulfonated polymer membrane if the
carboxylate polymer membrane is able to transfer moisture from one
of its sides to the other side. A carboxylate polymer membrane
shall mean a layer of polymer comprising a carboxylate ion
(CO.sub.2.sup.-/+) within its chemical structure, wherein the
carboxylate ion (CO.sub.2.sup.-/+) is typically located within the
side chain of the polymer. An example of a generic chemical
structure for a carboxylate polymer membrane would include the
examples of a generic chemical structure for a sulfonated polymer
membrane described hereinbefore and wherein the SO.sub.3.sup.- ion
is replaced with a CO.sub.2.sup.- ion. Although the remainder of
this discussion shall refer to sulfonated polymer membranes, it
shall be understood that other ionomer membranes, such as
carboxylated polymer membranes, could be used as the material from
which the plates 20 are constructed.
[0050] Referring to FIG. 3, each plate 20 typically is rectilinear
having alternate pairs of sides (i.e., four sides). Spacer bars 22
are interposed between alternating plates 20 and located along two
opposing sides of such plates 20, thereby forming an array of first
passageways 26. The spacer bars 22 seal (e.g., closes or blocks)
and define the first passageways 26 such that a first gas stream
passes therethrough in a direction indicated by the arrow marked A.
In the same respect, spacer bars 24 are interposed between
alternate pairs of plates 20, other than those pairs that contain
spacer bars 22, and are located along two opposing sides of such
plates 20, thereby forming an array of second passageways 28. The
spacer bars 24 seal and define the second passageways 28 such that
a second gas stream passes therethrough in a direction indicated by
the arrow marked B, which is substantially perpendicular to the
arrow A. Although the spacer bars 22 and the spacer bars 24 are
perpendicular to one another, thereby depicting a cross flow heat
exchanger, it shall be understood that the spacer bars 22, 24 can
be oriented to create a parallel or a counter flow heat exchanger.
Provided the plates 20 have sufficient stiffness, the spacer bars
22, 24 not only serve as a means for sealing the sides of the
plates 20 to create the alternating passageways 26, 28, but also
simultaneously serve as a means for spacing the plates 20 apart
from one another.
[0051] As discussed in U.S. Pat. No. 5,785,117, which is hereby
incorporated by reference, an additional means for sealing the
sides of the plates 20 to create the alternating passageways 26,
28, may include creating a flange with the opposite sides of the
plates 20. Specifically, referring to FIG. 4, two opposing sides of
a plate 20 are bent in one direction at approximately 90.degree. to
create flanges 52. The other two opposing sides of the same plate
20 are also bent in the opposite direction at approximately
90.degree. to create flanges 54. The next adjacent plate 20 has two
sets of opposing sides wherein, one set has flanges 56 bent in one
direction at approximately 90.degree. and the other set has flanges
58 bent in the opposite direction at approximately 90.degree.. When
these two plates are adjacent to one another, the flanges 54 and
the flanges 56 overlap to create passageway 28 and seal the sides
of such passageway. When the next pair of plates 20 are adjacent to
one another, the flanges 52 and the flanges 58 overlap and create
passageway 26 and seal the sides of such passageway. Although not
shown, a further means for sealing a pair of plates 20 to create a
passageway may include placing an adhesive tape or a face plate, or
another type of obstruction between the space between of two plates
20.
[0052] Referring to FIG. 5, once the sealing means and the plates
20 are assembled to create the passageways 26, 28, the plate-type
heat exchanger 12a is formed. Although this figure depicts a
plate-type heat exchanger 12a having a total of six alternating
passageways 26, 28, the plate-type heat exchanger 12a may have as
few as two passageways, or as many passageways as are required to
transfer the desirable amount of heat from one gas stream to the
other. FIG. 5 illustrates a plate-type heat exchanger 12a having a
sealing means located at the sides of the plates 20, thereby
leaving the remainder of each plate 20 unsupported. Hence, it is
preferable that the plates 20 have sufficient rigidity (i.e.,
stiffness) to prevent them from fluttering while the gas streams
pass through the passageways 26, 28. Creating a plate 20 with such
rigidity, however, may require increasing the thickness of the
plates 20, which, in turn, may reduce its thermal efficiency.
Therefore, it may be desirable to reduce the thickness of the
plates 20 and insert an alternate means for providing the spacing
of the parallel plates.
[0053] Referring to FIG. 6, there is shown an alternate embodiment
of the plate-type heat exchanger 12b of the present invention.
Unlike the plate-type heat exchanger 12a in FIG. 5, which does not
provide support across the width of the plate 20, the plate-type
heat exchanger 12b in FIG. 6 includes a continuous corrugated sheet
30 interposed between the plates 20, thereby preventing the plates
20 from fluttering as the gas streams pass through the passageways
26, 28. The continuous corrugated sheet 30 is typically constructed
of paper but may also be constructed of metal or plastic. The
continuous corrugated sheet 30 also serves as an alternate means
for spacing the plates 20 apart from one another. Specifically, the
alternating peaks 32, 34 of the continuous corrugated sheet 30
contact the plates 20 and create a passageway for gas stream to
flow in the same direction as the corrugations. Moreover, the
continuous corrugated sheet 30 not only serves as a means of
spacing apart the plates 20, but also simultaneously serves as a
means for sealing two opposite sides of the gap between the plates
20. In other words, as the alternating peaks 32, 34 of the
continuous corrugated sheet 30 contact the plates 20, the contact
points act as a seal line and prevent the gas stream from flowing
across the continuous corrugated sheet 30.
[0054] Referring to FIG. 7, there is shown an alternate embodiment
of the plate-type heat exchanger 12c of the present invention. The
plate-type heat exchanger 12c in FIG. 7 replaces the continuous
corrugated sheet 30 within the plate-type heat exchanger 12c
illustrated in FIG. 6, with a corrugated lattice structural sheet
36. Referring to FIG. 8, there is shown a three dimensional view of
the corrugated lattice structural sheet 36, as described in U.S.
Pat. Nos. 5,527,590, 5,679,467, and 5,962,150, which are hereby
incorporated by reference. Referring to FIG. 8A, there is shown an
enlarged view of a portion of the corrugated lattice structural
sheet 36 in FIG. 8, constructed from a plurality of uniformly
stacked pyramids in a three dimensional array. Each pyramid is
constructed of intersecting cross members 60 that intersect at the
vertex 61 of the pyramid. An example of such a corrugated lattice
structural sheet includes that which is manufactured by Jamcorp of
Wilmington, Mass. and distributed under the tradename LATTICE BLOCK
MATERIAL (LBM). The corrugated lattice structural sheet 36 is
typically constructed of metal, plastic, or rubber.
[0055] Unlike the continuous corrugated sheet 30, which contacts
the plate 20 along the entire length of its the peaks 32 and
valleys 34, the corrugated lattice structural sheet 36 only
contacts the plate 20 at the vertices 61 of the pyramids, thereby
reducing the surface area of the sheet that contacts the plate 20
and increasing the plate's 20 effectiveness for transferring energy
from one passageway to the other. Moreover, referring back to FIG.
6, in order to transfer the heat in the portion of the passageway
26 marked 38 to the portion of the passageway 28 marked 40, the
heat must pass through both the continuous corrugated sheet 30 and
the plate 20. Therefore, the inclusion of the continuous cornigated
sheet 30 between the plates 20 limits the amount of available
surface area for the latent heat to directly pass through the plate
20 from passageway 26 to passageway 28.
[0056] Referring to FIGS. 9 and 10, which are cross sections of the
plate-type heat exchanger 12c illustrated in FIG. 7 taken along
lines 9-9 and 10-10 respectively, in order to transfer heat from
passageway 26 to passageway 28, the heat need only pass through the
plate 20. Because the corrugated lattice structural sheet 36 is an
open structure, the gas stream is able to flow freely throughout
the passageways 26, 28. Additionally, because the corrugated
lattice structural sheet 36 only makes point contact with the plate
20, the majority of surface area on the plate 20 is available to
transfer heat from one passageway to the other. Compared to the
continuous corrugated sheet 30, the corrugated lattice structural
sheet 36 is a more efficient means for spacing apart the plates 20
from one another. Furthermore, the design of the lattice structural
sheet 36 may mix (i.e., stir) the gas stream as it passes through
the passageways 26, 28, thereby increasing the effectiveness factor
of the plate-type heat exchanger 12c. However, because the
corrugated lattice structural sheet 36 is an open structure, the
plate-type heat exchanger 12c requires a means for sealing two
opposing sides of the passageways 26, 28, thereby allowing the gas
streams to pass therethrough in respective first and second
directions. The sealing means may comprise spacer bars 22, 24 as
illustrated in FIGS. 3 and 4 or any other sealing means discussed
hereinbefore.
[0057] Referring to FIG. 11, there is shown an alternate embodiment
of the present invention. Specifically, FIG. 11 is a side view of a
plate 20 interposed between two planar lattice sheets 52. Although
this figure illustrates a planar lattice sheet 52 adjacent to both
sides of the plate 20, it may be sufficient that a single planar
lattice sheet 52 be adjacent to one side of the plate 20 if the
mechanical characteristics of the plate 20 and/or the planar
lattice sheet 52 provide adequate structural support. Referring to
FIG. 12, there is shown a top view of a planar lattice sheet 52,
which is constructed of a plurality of segments 54 forming an array
of two dimensional trigonal structures, wherein the segments 54
intersect at intersection points 56. The planar lattice sheet 52 in
FIG. 12 differs from the corrugated lattice structural sheet 36 in
FIG. 8A in that the corrugated lattice structural sheet 36
typically forms three-dimensional pyramid-type structures at the
intersection points of the cross members, while the planar lattice
sheet 52 typically forms a two-dimensional trigonal structure from
overlapping segments 54. In other words, the height of the
corrugated lattice structural sheet 36 is the height of the vertex
of the pyramid type structures formed therein, but the height of
the planar lattice sheet 52 is equal to the thickness of the
segments 54. Therefore, the corrugated lattice structural sheet 36
is typically thicker than the planar lattice sheet 52. The area
indicated by reference numeral 58 is open space. Therefore, placing
the sheet 20 between two planar lattice sheets 52 supports the
sheet 20 and maintains its flat profile while allowing the gas
streams to access the maximum amount of surface area on the plate
20 as the two gas streams pass through the passageways 26, 28.
[0058] Referring to FIG. 13, if both the planar lattice sheets 52
and the corrugated lattice structural sheet 36 are incorporated
into a plate-type heat exchanger, it is preferable to coordinate
their respective designs. Specifically, it is preferable that the
vertex 61 of pyramids in the corrugated lattice structural sheet 36
align (i.e., contact or connect) with the intersection points 56 of
the segments 54 in the planar lattice sheet 52. Hence, two plates
20 are supported by adjacent planar lattice sheets 52, and a
corrugated lattice structural sheet 36 is interposed between the
planar lattice sheets 52, thereby providing maximum support for the
plate-type heat exchanger 12c and allowing the maximum amount of
energy transfer between the gas streams in the passageways 26,
28.
[0059] Referring to FIG. 14, there is shown an alternate embodiment
of the plate-type heat exchanger 12d of the present invention.
Unlike the plate-type heat exchanger 12b in FIG. 6 and the
plate-type heat exchanger 12c in FIG. 7, the plate-type heat
exchanger 12d in FIG. 14 does not include a partial obstruction,
such as the continuous corrugated sheet 30 and corrugated lattice
structural sheet 36, within the passageways 26, 28 to support the
plates 20 or keep them apart from one another. Rather, the plates
20 in the plate-type heat exchanger 12d of FIG. 14 are supported by
a sheet of webbed netting 42. The webbed netting 42 is typically
constructed of plastic, which is compatible with the sulfonated
polymer membrane such that webbed netting 42 will adhere to the
membrane regardless of whether the webbed netting 42 is adjacent
the membrane or embedded therein: The strand thickness and the
spacing between the nodes are chosen to provide the required
stiffness to the sulfonated polymer membrane, while maximizing the
membrane's surface area that is exposed to the gas stream.
Referring to FIGS. 15 and 16, which are cross sections of the
plate-type heat exchanger 12d illustrated in FIG. 14 taken along
lines 15-15 and 16-16 respectively, the plate 20 is interposed
between sheets of webbed netting 42, which reinforces the plate 20.
Referring to FIG. 17, which is a cross section of the plate-type
heat exchanger illustrated in FIG. 15 taken along line 17-17, this
figure illustrates the top view of the webbed netting 42 laid over
the plate 20. Referring back to FIGS. 15 and 16, because the
passageways 26, 28 are unobstructed, the plate-type heat exchanger
12d requires a means for sealing two opposing sides of the
passageways 26, 28, thereby allowing the gas streams to pass
therethrough in respective first and second directions. The sealing
means may comprise spacer bars 22, 24 as illustrated in FIGS. 3 and
4, or any other sealing means discussed hereinbefore.
[0060] Referring to FIG. 18, there is shown another alternate
embodiment of the webbed supported plate illustrated in FIGS. 15
and 16. Unlike plate 20 illustrated in FIGS. 15 and 16 which is
supported by a sheet of webbed netting 42 on both sides, the plate
20 in FIG. 18 is only supported by one sheet of webbed netting 42
adjacent the plate 20. Although FIG. 18 depicts the sheet of webbed
netting 42 on top of the plate 20, the webbed netting 42 may also
be placed below the plate 20. Therefore, depending upon the
stiffness of the plate 20 and the webbed netting 42, the plate 20
may be supported by one or two sheets of webbed netting 42 that are
situated above and/or below the plate 20.
[0061] Referring to FIG. 19, there is shown another alternate
embodiment of the webbed supported plate. This figure illustrates
the webbed netting 42 embedded within the plate 20, thereby
increasing the stiffness of the plate 20. If the sulfonated polymer
membrane is typically made from an extrusion process, this
structure may be formed by casting the sulfonated polymer over the
webbed netting 42.
[0062] Referring to FIG. 20, there is shown another alternate
embodiment of the present invention which replaces the layers of
webbed netting 42 with layers of plastic 46 to provide additional
support to the plate 20. Specifically, the plate 20, which is
constructed of a sulfonated polymer membrane, is interposed between
two layers of plastic 46, such as polytetrafluroehtylene (PTFE),
expanded polytetrafluoroethylene (ePTFE), polypropylene, or other
porous (i.e., open cell) polymer film that permits air permeation
while minimizing the pressure drop of the passing air stream.
Referring to FIG. 21, depending upon the stiffness of the plastic
layer 46 and the plate 20, the plastic layer 46 may be adjacent to
one side of the plate 20, and the adjacent side may be on the top
or bottom of the plate 20.
[0063] Referring to FIG. 22 there is shown another alternate
embodiment of the plate-type heat exchanger 12e that includes an
alternate layer of webbed netting 48 between the plates 20.
Specifically, the layer of webbed netting 48 includes nodes 50 that
have a diameter equal to the height of the passageways 26, 28. The
nodes 50 are the intersection points of the strands. Therefore,
referring to FIGS. 23 and 24, which are cross sections of the
plate-type heat exchanger 12e illustrated in FIG. 22 taken along
lines 23-23 and 24-24 respectively, the layer of webbed netting 48
is interposed between the plates 20 such that the nodes 50 contact
the plates 20. This contact serves as a means for spacing apart the
plates 20, which are also supported by the webbed netting 48.
Because the nodes 50 are distributed within the layer of webbed
netting 48, the nodes 50 do not form a seal with the plates 20.
Hence, the layer of webbed netting 48 is an open structure, thereby
requiring the plate-type heat exchanger 12e to include a means for
sealing two opposing sides of the passageways 26, 28 to the gas
streams to pass therethrough in respective first and second
directions. The sealing means may comprise spacer bars 22, 24 as
illustrated in FIGS. 3 and 4 or any other sealing means discussed
hereinbefore.
[0064] Although the invention has been described and illustrated
with respect to the exemplary embodiments thereof, it should be
understood by those skilled in the art that the foregoing and
various other changes, omissions and additions may be made without
departing from the spirit and scope of the invention.
* * * * *